Compendium Review
Chapter 1 – Exploring Life and Science
Sub-Topics:
The 7 Characteristics of Life
Humans are Related to other animals
Science is a process
Making sense of a scientific study
Science and Social Responsibility
Chapter 1 – Exploring Life and Science
Sub-Topics:
The 7 Characteristics of Life
Humans are Related to other animals
Science is a process
Making sense of a scientific study
Science and Social Responsibility
Living organisms all share 7 common characteristics.
1. They all have levels of organization- atoms join to from molecules that make up a cell. A cell is the smallest structural and functional unit of an organism. A tissue is a group of similar cells that perform the same function. Tissues make up organs and each organ belongs to an organ system. An organ system works together to accomplish a common purpose for a living organism. Organisms such as plants or humans are a collection of organ systems. All the levels of biological organization extend beyond the individual into groups of species. (Breeding organisms), which makes up that particular species. The population of various organisms makes a community. The environment around the community makes the ecosystem and finally the earth’s ecosystem makes the biosphere.
2. All things take material and energy from the environment. Humans and other animals acquire materials and energy when they eat food. Food provides nutrients to provide energy to maintain the organization of the cell and of the organism. Some nutrient molecules are broken down completely to provide the necessary energy to convert other nutrient molecules into the parts and products of the cell.
3. Organisms reproduce offspring that resemble themselves to ensure continuance of their own kind. The presence of genes or DNA molecules allows cells and organisms to make more of them. DNA contains the blue prints of the organism as to duplicate themselves.
4. Growth and development is recognized by and increase in size and often the number of cells. In humans development includes all the changes that occur from the time the egg is fertilized until death. All organisms undergo development.
5. This will be discussed in depth later.
6. Organisms respond to external stimuli, often moving away from, or toward. Movement in humans and other animals is dependent upon their nervous and musculoskeletal systems. The leaves of plants track the passage of the sun during the day and when a house plant is placed near a window; its stems bend to face the sun. Homeostasis would be impossible without the ability of the body to respond to stimuli.
7. Organisms have an evolutionary history and adapt to their environment and changes. When a new variation arises that allows certain members of the species to capture more resources, these members tend to survive and to have more offspring that the other, unchanged members. Therefore, each successive generation will include more members with the new variation that represents and adaption to the environment.
Humans Are Related to Other Animals
The Classification of living things mirrors their evolutionary relationships. Humans are mammals, a type of vertebrate in domain Eurkarya. Humans differ from other mammals, including apes, by their highly developed brains, completely upright stance, creative language and ability to use a wide variety of tools.
Humans Have a Culture Heritage – Human beings encompass certain activities and products that are passed on from one generation to the next outside of direct biological inheritance. The previous generation passes on their beliefs, values, and skills to the next generation. Human skills have also produced a rich heritage in the arts and sciences. This culture of highly civilized people gives us the impression we are separate from other animals and makes us think we are not a part of nature.
Humans are part of the biosphere – Humans depend on the biosphere for its man services, such as absorption of pollutants, sources of water and food, prevention of soil erosion, and natural beauty. Unfortunately humans also threaten the biosphere with the many products and activities they use in there lives. Many biologists are alarmed about the present rate of extinction and believe it may eventually rival the rates of the five ass extions that have occurred during our plants history. The dinosaurs became extinct during the last mass extinction 65 million years ago. One of the major bioethical issues of our time is preservation or the biosphere. Conservation, recycling, a preservation is the way we can help ensure the continued existence of our species.
Science as a process
Science is a way of knowing about the natural world. Biologists use the scientific process when they study the natural world. A hypothesis is formulated and tested to arrive at a conclusion. Scientists have developed traditional methods that give them added confidence in the conclusions of studies.
Importance of scientific Theories in Biology – Scientific theories are concepts that tell us about the order and patterns with the natural world.
Science is a way of knowing about the natural world. Biologists use the scientific process when they study the natural world. A hypothesis is formulated and tested to arrive at a conclusion. Scientists have developed traditional methods that give them added confidence in the conclusions of studies.
Importance of scientific Theories in Biology – Scientific theories are concepts that tell us about the order and patterns with the natural world.
The Scientific Method has Steps
· Observation – New observations are mad and previous data are studied
· Hypothesis- Input from various sources is used to formulate a testable statement.
· Experiment/Observations – The hypothesis is tested by experiment or further observations
· Conclusion – The results are analyzed and the hypothesis is supported or rejected.
· Scientific Theory – Many experiments and observations support a theory
How to do a Controlled Study
1. State Hypothesis
2. Gather Large Number of Subjects
3. Divide Subjects into three groups
a. Control Group
b. Test Group 1
c. Test Group 2
4. Perform Experiment
Scientific Journal Versus other Sources of Information – Scientific journals are highly regarded by most scientists. The investigator who did the research is usually the primary author of a the published study. The studies in scientific journals may be very technical and difficult for a layperson to read and understand. The general public normally relies on second hand information, which means they could be misinformed by someone not understanding the results or verifying the accuracy of the study. Be careful of scientific information on the internet. Credible scientific information can be found at websites with URLs containing .edu, .gov, or org.
Making Sense of a Scientific Study
When evaluating a study it is important to consider the type of data (testimonials are never considered reliable data).
What to Look for – The methodology is most important to look at. Verifying how the study was performed, how they conducted it and what the results or data tell us what they discovered. The conclusion must be read last because it is the interpretation of the person conducting the study. It is not the same as the data.
Chapter 2 From Atoms to Molecules – Anything that takes up space is matter…Its all matter.
1. State Hypothesis
2. Gather Large Number of Subjects
3. Divide Subjects into three groups
a. Control Group
b. Test Group 1
c. Test Group 2
4. Perform Experiment
Scientific Journal Versus other Sources of Information – Scientific journals are highly regarded by most scientists. The investigator who did the research is usually the primary author of a the published study. The studies in scientific journals may be very technical and difficult for a layperson to read and understand. The general public normally relies on second hand information, which means they could be misinformed by someone not understanding the results or verifying the accuracy of the study. Be careful of scientific information on the internet. Credible scientific information can be found at websites with URLs containing .edu, .gov, or org.
Making Sense of a Scientific Study
When evaluating a study it is important to consider the type of data (testimonials are never considered reliable data).
What to Look for – The methodology is most important to look at. Verifying how the study was performed, how they conducted it and what the results or data tell us what they discovered. The conclusion must be read last because it is the interpretation of the person conducting the study. It is not the same as the data.
Chapter 2 From Atoms to Molecules – Anything that takes up space is matter…Its all matter.
Units:
From Atoms to Molecules
Water and Living Things
Molecules of Life
Carbohydrates
Lipids
Proteins
Nucleic Acids
From Atoms to Molecules
Water and Living Things
Molecules of Life
Carbohydrates
Lipids
Proteins
Nucleic Acids
· Elements are on of the basic building blocks of matter. Elements cannot be broken down by chemical means. There are only 92 naturally occurring elements. It surprising that over 90% of the human body is composed of just four elements: Carbon, nitrogen, oxygen, and hydrogen. Every element has a name and a symbol. Chemists arranged the elements in a periodic tale which has this name because all the elements in a column undergo the same type of chemical reaction.
· Atoms are the smallest unit of an element that still retains the chemical and physical properties of the element. The atom being so small still contains even smaller subatomic particles called protons and neutrons, located in the nucleus and electrons orbit about the nucleus n the shells. Protons carry a positive chare and electrons have negative charge. The atomic numbers given in the periodic table tell you how many protons and therefore hoe many electrons an atom has when it is electrically neutral. The mass of an atom represents its quantity of matter. The subatomic particles are so light that their mass is indicated by special designations called atomic mass units. Protons and neutrons are assigned one atomic mass unit and electrons have almost no mass. The atom is mass for each element allows you to determine the number of neutrons these atoms have.
· Isotopes of the same type of atom differ in the number of neutrons and therefore mass. Carbon 12 has six neutrons, carbon 13 has seven neutrons, and carbon 14 has eight neutrons. Carbon 14 is unstable and begins to break down releasing radioisotopes.
o Low levels of radiation are important in chemistry, biology, and medicine in the use of many diagnostic scans such as the PET scan.
o High levels of radiation are used in the treatment of cancer. High levels are also used in the sterilization technique of medical and dental equipment.
· Molecules and Compounds – A molecule is a chemical unit when atoms bond with one another. The atoms can be different as when atoms join to make water which is considered to be a compound. The tow types of bonds that join atoms are called the ionic bond and the covalent bond.
o Ionic Bonding occurs when atoms give up or take on an electron in order to achieve a stable outer shell. Ions are particle that carry either a positive or negative charge. The attraction between oppositely charged sodium ions and chloride ions forms and ionic bond.
o Covalent boning occurs when atoms share electrons. The electrons spend part their time n the outer shell of each atom therefore they are counted as belonging to both the bonded atoms.
§ Double and triple bonds share two or three pairs of between them
o High levels of radiation are used in the treatment of cancer. High levels are also used in the sterilization technique of medical and dental equipment.
· Molecules and Compounds – A molecule is a chemical unit when atoms bond with one another. The atoms can be different as when atoms join to make water which is considered to be a compound. The tow types of bonds that join atoms are called the ionic bond and the covalent bond.
o Ionic Bonding occurs when atoms give up or take on an electron in order to achieve a stable outer shell. Ions are particle that carry either a positive or negative charge. The attraction between oppositely charged sodium ions and chloride ions forms and ionic bond.
o Covalent boning occurs when atoms share electrons. The electrons spend part their time n the outer shell of each atom therefore they are counted as belonging to both the bonded atoms.
§ Double and triple bonds share two or three pairs of between them
Water and Living Things
Water is the most abundant molecule in living organisms. In water the electrons spend more time circling the oxygen because it is bigger than the hydrogen creating more of an attraction for the electron. Water is polar because the oxygen end of the molecule has a slight negative charge and the hydrogen end has a positive charge.
Hydrogen Bonds – Occur whenever a covalently bonded hydrogen is slightly positive and attracted to a negatively charge atom some distance away.
Water is the most abundant molecule in living organisms. In water the electrons spend more time circling the oxygen because it is bigger than the hydrogen creating more of an attraction for the electron. Water is polar because the oxygen end of the molecule has a slight negative charge and the hydrogen end has a positive charge.
Hydrogen Bonds – Occur whenever a covalently bonded hydrogen is slightly positive and attracted to a negatively charge atom some distance away.
Properties of Water – Water molecules are cohesive because of their polarity and hydrogen bonding. Water has many characteristics due to this bonding action.
1. Water is liquid at room temperature because the compounds with a low molecular weight are usually gases at room temperature.
2. Water temperature changes slowly due to the many hydrogen bonds that link water molecules. This means water can take much heat before boiling.
3. Water takes a large amount of heat change it to stem
4. Frozen water is less dense that liquid water so ice can float on water.
5. Water molecules are cohesive and therefore liquids fill vessels, such as blood vessels. After blood transports oxygen and nutrients to cells these molecules are used to produce cellular energy. Blood also removes wastes such as carbon dioxide from cells.
6. Water is also a solvent in our bodies used for balancing chemical reactions.
1. Water is liquid at room temperature because the compounds with a low molecular weight are usually gases at room temperature.
2. Water temperature changes slowly due to the many hydrogen bonds that link water molecules. This means water can take much heat before boiling.
3. Water takes a large amount of heat change it to stem
4. Frozen water is less dense that liquid water so ice can float on water.
5. Water molecules are cohesive and therefore liquids fill vessels, such as blood vessels. After blood transports oxygen and nutrients to cells these molecules are used to produce cellular energy. Blood also removes wastes such as carbon dioxide from cells.
6. Water is also a solvent in our bodies used for balancing chemical reactions.
Acids and Bases – A mole is a unit of scientific measurement for atoms, ions, and molecules.
· Acidic Solutions -Acid solutions are substances that dissociate in water, releasing hydrogen ions.
· Basic Solutions -Base solutions are substances that either take up hydrogen ions or release hydroxide ions.
· pH Scale - The pH scale is used to indicate the acidity and basicity or alkalinity of a solution. A number with a smaller negative exponent indicates a greater quantity of hydrogen ions than one with a larger negative exponent. Basic solutions have fewer hydrogen ions.
· Buffers -The pH of body fluids needs to be maintained within a narrow range or else health suffers. The environment has buffer to take care of problems that arise. Buffer help keep the ph within normal limits because they are chemicals or combinations of chemicals that take up excess hydrogen ions.
· Acidic Solutions -Acid solutions are substances that dissociate in water, releasing hydrogen ions.
· Basic Solutions -Base solutions are substances that either take up hydrogen ions or release hydroxide ions.
· pH Scale - The pH scale is used to indicate the acidity and basicity or alkalinity of a solution. A number with a smaller negative exponent indicates a greater quantity of hydrogen ions than one with a larger negative exponent. Basic solutions have fewer hydrogen ions.
· Buffers -The pH of body fluids needs to be maintained within a narrow range or else health suffers. The environment has buffer to take care of problems that arise. Buffer help keep the ph within normal limits because they are chemicals or combinations of chemicals that take up excess hydrogen ions.
Molecules of Life
Carbohydrates, lipids, proteins, and nucleic acids are the four categories of organic molecules. In biology organic refers to a molecule that contains carbon and hydrogen and is usually associated with living things.
· Carbohydrates – are combined of 2:1 ratio of hydrogen to oxygen atoms which explains the name hydrates of carbon. Carbohydrates release quick and short term energy.
o Simple carbohydrates include
§ Monosaccharide
§ Pentose
§ Hexose
§ Glucose
o Complex Carbohydrates include
§ Polysaccharides – These are macromolecules such as starch, glycogen and cellulose. Cellulose is found in plant cell walls. Starch and glycogen are readily stored forms of glucose in plants and animals.
· Lipids – are fats in animals and oils in plants and contain more energy per gram than other biological molecules. Lipids are diverse in structure and function but have common characteristics. They are not water soluble. A fatty acid is a carbon-hydrogen chain that ends with the acidic group –COOH. Saturated fatty acids have no double bonds between the carbon atoms. Unsaturated fatty acids have double bonds in the carbon chain wherever the number of hydrogen’s is less than two per carbon.
· Proteins – are of primary importance in the structure of function of cells. They function as support, enzymes, transportation, defense, hormones, and motion.
· Amino Acids- are subunits of proteins.
· Nucleic Acids- are the DNA and RNA . DNA stores genetic information in the cell and in the organism. DNA replicates and transmits this information when a cell reproduces. RNA conveys DNA’s instructions DNA differs from RNA in the nucleotide structure. DNA contains the sugar deoxyribose and the nucleotides in RNA contain the sugar ribose, which is respective of their names.
· ATP- The energy carrier is when adenosine is modified by the addition of three phosphate groups instead of one it becomes ATP (adenosine triphosphate).
Chapter 3 What is A Cell?
Topics:
What is a Cell?
How Cells Are Organized
The plasma Membrane and How Substances Cross It
The Nucleus and the Production of Proteins
The Cytoskeleton and Cell Movement
Mitochondria and Cellular Metabolism
· Cell Theory – A cell is the basic unit f life. There is no smaller unit of life that is able to reproduce, respond to stimuli, remain homeostatic, grow and develop, take in and use materials from the environment, and become adapted to the environment. All living things are made of cells and they all look very different. Red blood cells look different than white blood cells. New cells can only come from preexisting cells.
· Cell Size – Few cells are large enough to see without a microscope. The larger the cell the more nutrients it needs.
· How Cells are organized – The first cells to arise were the prokaryotic cell which lacks a nucleus. Prokaryotic cells today are represented by the bacteria and Achaea. The eukaryotic cell which does have a nucleus is believed to have evolved from the Achaea. Bothe cells have a plasma membrane which regulates what enters and exits a cell. All types of cells also contain cytoplasm, which s a semi fluid medium that contains water and various types of molecules suspended of dissolved in the medium.
· The Plasma Membrane and How Substances Cross It – the plasma membrane marks the boundary between the outside and the inside of the cell, which is necessary to the life of the cell. The plasma membrane is a phospholipids bi-layer with attached or embedded proteins. At body temperature the phospholipids bi-layer is a liquid. The membrane is keeps the cell intact allowing only the molecules and ions to enter and exit the cytoplasm freely.
· The Nucleus and the production of Proteins – The nucleus stores genetic information. Every cell contains the same genes, but each type of cell has certain genes which are segments of DNA. When looking at the nucleus you cannot see DNA, you see the chromatin undergoing coiling into rod like structure called chromosomes just before the cell divides. Each of the chromosomes contains a DNA molecule. The nucleus is separated from the cytoplasm by a double membrane known as the nuclear envelop, which is continuous with endoplasmic reticulum (ER)
· Ribosome’s – Are organelles composed of proteins and rRNA. Protein synthesis occurs at the ribosomes.
· The Endomembrane System – consists of the nuclear envelope and the endoplasmic reticulum, the Golgi apparatus, lysomes and vesicles.
· The Cytoskeleton and Cell Movement – the cell is crisscrossed by several types of protein fibers collectively called the cytoskeleton, which helps maintain the cells shape and either anchors the organelles and assists in the movement. The cytoskeleton contains Microtubules which are much larger than filaments. Each is a cylinder that contains 13 longitudinal rows of a protein called tubulin. During cell division microtubules form spindle fibers which assist the movement of chromosomes.
· Cilia and Flagella – both participate in movement. A cilium is about 20 times shorter than a flagellum but both have the same organization. They both grow from basal bodies.
· Mitochondria and Cellular Metabolism – The mitochondria is the power house the cell, it converts the glucose into the chemical energy ATP. During this process mitochondria uses oxygen and gives off CO2. This is called cellular respiration. The matrix of the mitochondria contains enzymes for breaking down glucose products. ATP production then occurs at the cristae. Proteins aid in the conversion of energy. The mitochondria are bound by a double membrane as a prokaryote would be if taken into a cell by endocytosis. Mitochondria also have their own genes and they can reproduce themselves.
· Cellular Respiration and Metabolism- Cellular respiration is very important in metabolism. Metabolism requires metabolic pathways that are carried out by enzymes. Each reaction in a metabolic pathway requires a specific enzyme. Enzymes are named for their substrates. Coenzymes are non-protein molecules that assist the activity of an enzyme and may even accept or contribute atoms to the reaction. Vitamins are often components of coenzymes. After blood transports glucose and oxygen to cells cellular respiration which breaks down glucose to CO2 and water begins. Three pathways are involved in the breakdown of glucose. These pathways allow the energy within a glucose molecule to be released slowly, so that ATP can be produced gradually. The citric acid cycle completes the breakdown of glucose. The cyclical series of enzymatic reaction occurs in the matrix of mitochondria and CO2 is released. The citric acid cycle also produces two ATP per glucose molecule.
Chapter 4 Organization and Regulation of Body Systems
Topics:
Types of Tissues
Connective Tissue Connects and Supports
Muscular Tissue Moves the Body
Nervous Tissue Communicates
Epithelial Tissue Protects
Cell Junctions
Integumentary System
Organ Systems
Homeostasis
· Types of Tissue- A tissue is composed of specialized cells of the same type that perfume a common function.
o Connective tissue binds and supports body parts
o Muscular tissue moves the body and its parts
o Nervous tissue receives stimuli and conducts nerve impulses
o Epithelial tissue covers body surfaces and lines body cavities
· Cell Junctions- Epithelial cells, nerve and muscle cells are connected by cell junctions that help a tissue perform its function. Cell junctions arise when plasma membranes are joined in these ways
o Tight junctions allow epithelial cells to form a layer that covers the surface or organs and line body cavities.
o Adhesion junctions attach cytoskeletal fibers of one cell to another.
o Gap junctions occur when adjacent plasma membranes converge and leave a small channel between them that small molecules can ions can diffuse through.
· Integumentary System is the largest organ system. It is composed of all four tissue types and has several accessory organs. It accounts for nearly 15% of the weight on humans. The skin has many functions, regulating body heat, protection from the environment, water loss, and homeostasis. The skin has two regions the epidermis and the dermis. A subcutaneous lay is found between them. The epidermis is the outmost layer and is made up of stratified squamous epithelium. The subcutaneous layer is the layer beneath the dermis that is composed of loose connective tissue and adipose tissue which stores fat. The dermis is made of dense fibrous connective tissue beneath the subcutaneous lay. The dermis contains collagen and elastic fibers, and blood vessels. The sensory receptors primarily in the dermis are specialized for touch, pressure, pain, hot, and cold.
· Accessory Organs of the Skin includes Nails, hair follicles, oil glands, and sweat glands.
· Organ Systems
o Integumentary System contains skin, nails, hairs, muscles that move the hairs, oil and sweat glands, blood vessels, and nerves.
o Cardiovascular system includes the heart and blood vessels t pump oxygen rich blood to all parts of the body
o Lymphatic system consists of lymphatic vessels, lymph nodes, the spleen, and other lymphatic organs to make up the immune system.
o Digestive system consists of the mouth, esophagus, stomach, small intestine, and large intestine. Other associated organs include teeth, tongue, salivary glands, liver, gallbladder, and pancreas.
o Respiratory System is the lungs and the airways taking air in and breathing it out.
o Urinary system contains the kidneys, the bladder, and the tubes that carry urine.
o Skeletal system includes all bones of the body that are used for protection, movement, and to store minerals.
o Muscular system accounts for the movement of the body and posture. The cardiac muscle contracts to pump the heart, and internal organ muscle are smooth muscle.
o Nervous system consists of the brain, spinal cord and nerves.
o Endocrine system is the hormonal glands.
o Reproductive system is different in male and female. In females the ovaries, oviducts, uterus, vagina, and external genitals. The male testes, other glands, and various ducts.
· Homeostasis – is the body’s ability to maintain a constant condition of its internal environment by adjusting its physiological processes, not through external conditions. There are two parts to the internal environment. Tissue fluid and blood. All of the body systems rely on homeostasis to remain healthy. When homeostatic mechanisms fail the result is poor health, disease, or death. Negative feedback is the primary homeostatic mechanism that keeps a variable such as the blood glucose level close to a particular value. A homeostatic mechanism has two components a sensor and a control center. Negative feedback is present when the output of the system dampens the original stimulus. Positive feedback brings about an ever greater change in the same direction. A positive feedback can be harmful as when a fever causes metabolic changes that push the fever still higher. Positive feedback loops such as those involved in childbirth, blood clotting, and t he digestion of proteins to assist the body in completing a process, but there is a definite cut off point.
Carbohydrates, lipids, proteins, and nucleic acids are the four categories of organic molecules. In biology organic refers to a molecule that contains carbon and hydrogen and is usually associated with living things.
· Carbohydrates – are combined of 2:1 ratio of hydrogen to oxygen atoms which explains the name hydrates of carbon. Carbohydrates release quick and short term energy.
o Simple carbohydrates include
§ Monosaccharide
§ Pentose
§ Hexose
§ Glucose
o Complex Carbohydrates include
§ Polysaccharides – These are macromolecules such as starch, glycogen and cellulose. Cellulose is found in plant cell walls. Starch and glycogen are readily stored forms of glucose in plants and animals.
· Lipids – are fats in animals and oils in plants and contain more energy per gram than other biological molecules. Lipids are diverse in structure and function but have common characteristics. They are not water soluble. A fatty acid is a carbon-hydrogen chain that ends with the acidic group –COOH. Saturated fatty acids have no double bonds between the carbon atoms. Unsaturated fatty acids have double bonds in the carbon chain wherever the number of hydrogen’s is less than two per carbon.
· Proteins – are of primary importance in the structure of function of cells. They function as support, enzymes, transportation, defense, hormones, and motion.
· Amino Acids- are subunits of proteins.
· Nucleic Acids- are the DNA and RNA . DNA stores genetic information in the cell and in the organism. DNA replicates and transmits this information when a cell reproduces. RNA conveys DNA’s instructions DNA differs from RNA in the nucleotide structure. DNA contains the sugar deoxyribose and the nucleotides in RNA contain the sugar ribose, which is respective of their names.
· ATP- The energy carrier is when adenosine is modified by the addition of three phosphate groups instead of one it becomes ATP (adenosine triphosphate).
Chapter 3 What is A Cell?
Topics:
What is a Cell?
How Cells Are Organized
The plasma Membrane and How Substances Cross It
The Nucleus and the Production of Proteins
The Cytoskeleton and Cell Movement
Mitochondria and Cellular Metabolism
· Cell Theory – A cell is the basic unit f life. There is no smaller unit of life that is able to reproduce, respond to stimuli, remain homeostatic, grow and develop, take in and use materials from the environment, and become adapted to the environment. All living things are made of cells and they all look very different. Red blood cells look different than white blood cells. New cells can only come from preexisting cells.
· Cell Size – Few cells are large enough to see without a microscope. The larger the cell the more nutrients it needs.
· How Cells are organized – The first cells to arise were the prokaryotic cell which lacks a nucleus. Prokaryotic cells today are represented by the bacteria and Achaea. The eukaryotic cell which does have a nucleus is believed to have evolved from the Achaea. Bothe cells have a plasma membrane which regulates what enters and exits a cell. All types of cells also contain cytoplasm, which s a semi fluid medium that contains water and various types of molecules suspended of dissolved in the medium.
· The Plasma Membrane and How Substances Cross It – the plasma membrane marks the boundary between the outside and the inside of the cell, which is necessary to the life of the cell. The plasma membrane is a phospholipids bi-layer with attached or embedded proteins. At body temperature the phospholipids bi-layer is a liquid. The membrane is keeps the cell intact allowing only the molecules and ions to enter and exit the cytoplasm freely.
· The Nucleus and the production of Proteins – The nucleus stores genetic information. Every cell contains the same genes, but each type of cell has certain genes which are segments of DNA. When looking at the nucleus you cannot see DNA, you see the chromatin undergoing coiling into rod like structure called chromosomes just before the cell divides. Each of the chromosomes contains a DNA molecule. The nucleus is separated from the cytoplasm by a double membrane known as the nuclear envelop, which is continuous with endoplasmic reticulum (ER)
· Ribosome’s – Are organelles composed of proteins and rRNA. Protein synthesis occurs at the ribosomes.
· The Endomembrane System – consists of the nuclear envelope and the endoplasmic reticulum, the Golgi apparatus, lysomes and vesicles.
· The Cytoskeleton and Cell Movement – the cell is crisscrossed by several types of protein fibers collectively called the cytoskeleton, which helps maintain the cells shape and either anchors the organelles and assists in the movement. The cytoskeleton contains Microtubules which are much larger than filaments. Each is a cylinder that contains 13 longitudinal rows of a protein called tubulin. During cell division microtubules form spindle fibers which assist the movement of chromosomes.
· Cilia and Flagella – both participate in movement. A cilium is about 20 times shorter than a flagellum but both have the same organization. They both grow from basal bodies.
· Mitochondria and Cellular Metabolism – The mitochondria is the power house the cell, it converts the glucose into the chemical energy ATP. During this process mitochondria uses oxygen and gives off CO2. This is called cellular respiration. The matrix of the mitochondria contains enzymes for breaking down glucose products. ATP production then occurs at the cristae. Proteins aid in the conversion of energy. The mitochondria are bound by a double membrane as a prokaryote would be if taken into a cell by endocytosis. Mitochondria also have their own genes and they can reproduce themselves.
· Cellular Respiration and Metabolism- Cellular respiration is very important in metabolism. Metabolism requires metabolic pathways that are carried out by enzymes. Each reaction in a metabolic pathway requires a specific enzyme. Enzymes are named for their substrates. Coenzymes are non-protein molecules that assist the activity of an enzyme and may even accept or contribute atoms to the reaction. Vitamins are often components of coenzymes. After blood transports glucose and oxygen to cells cellular respiration which breaks down glucose to CO2 and water begins. Three pathways are involved in the breakdown of glucose. These pathways allow the energy within a glucose molecule to be released slowly, so that ATP can be produced gradually. The citric acid cycle completes the breakdown of glucose. The cyclical series of enzymatic reaction occurs in the matrix of mitochondria and CO2 is released. The citric acid cycle also produces two ATP per glucose molecule.
Chapter 4 Organization and Regulation of Body Systems
Topics:
Types of Tissues
Connective Tissue Connects and Supports
Muscular Tissue Moves the Body
Nervous Tissue Communicates
Epithelial Tissue Protects
Cell Junctions
Integumentary System
Organ Systems
Homeostasis
· Types of Tissue- A tissue is composed of specialized cells of the same type that perfume a common function.
o Connective tissue binds and supports body parts
o Muscular tissue moves the body and its parts
o Nervous tissue receives stimuli and conducts nerve impulses
o Epithelial tissue covers body surfaces and lines body cavities
· Cell Junctions- Epithelial cells, nerve and muscle cells are connected by cell junctions that help a tissue perform its function. Cell junctions arise when plasma membranes are joined in these ways
o Tight junctions allow epithelial cells to form a layer that covers the surface or organs and line body cavities.
o Adhesion junctions attach cytoskeletal fibers of one cell to another.
o Gap junctions occur when adjacent plasma membranes converge and leave a small channel between them that small molecules can ions can diffuse through.
· Integumentary System is the largest organ system. It is composed of all four tissue types and has several accessory organs. It accounts for nearly 15% of the weight on humans. The skin has many functions, regulating body heat, protection from the environment, water loss, and homeostasis. The skin has two regions the epidermis and the dermis. A subcutaneous lay is found between them. The epidermis is the outmost layer and is made up of stratified squamous epithelium. The subcutaneous layer is the layer beneath the dermis that is composed of loose connective tissue and adipose tissue which stores fat. The dermis is made of dense fibrous connective tissue beneath the subcutaneous lay. The dermis contains collagen and elastic fibers, and blood vessels. The sensory receptors primarily in the dermis are specialized for touch, pressure, pain, hot, and cold.
· Accessory Organs of the Skin includes Nails, hair follicles, oil glands, and sweat glands.
· Organ Systems
o Integumentary System contains skin, nails, hairs, muscles that move the hairs, oil and sweat glands, blood vessels, and nerves.
o Cardiovascular system includes the heart and blood vessels t pump oxygen rich blood to all parts of the body
o Lymphatic system consists of lymphatic vessels, lymph nodes, the spleen, and other lymphatic organs to make up the immune system.
o Digestive system consists of the mouth, esophagus, stomach, small intestine, and large intestine. Other associated organs include teeth, tongue, salivary glands, liver, gallbladder, and pancreas.
o Respiratory System is the lungs and the airways taking air in and breathing it out.
o Urinary system contains the kidneys, the bladder, and the tubes that carry urine.
o Skeletal system includes all bones of the body that are used for protection, movement, and to store minerals.
o Muscular system accounts for the movement of the body and posture. The cardiac muscle contracts to pump the heart, and internal organ muscle are smooth muscle.
o Nervous system consists of the brain, spinal cord and nerves.
o Endocrine system is the hormonal glands.
o Reproductive system is different in male and female. In females the ovaries, oviducts, uterus, vagina, and external genitals. The male testes, other glands, and various ducts.
· Homeostasis – is the body’s ability to maintain a constant condition of its internal environment by adjusting its physiological processes, not through external conditions. There are two parts to the internal environment. Tissue fluid and blood. All of the body systems rely on homeostasis to remain healthy. When homeostatic mechanisms fail the result is poor health, disease, or death. Negative feedback is the primary homeostatic mechanism that keeps a variable such as the blood glucose level close to a particular value. A homeostatic mechanism has two components a sensor and a control center. Negative feedback is present when the output of the system dampens the original stimulus. Positive feedback brings about an ever greater change in the same direction. A positive feedback can be harmful as when a fever causes metabolic changes that push the fever still higher. Positive feedback loops such as those involved in childbirth, blood clotting, and t he digestion of proteins to assist the body in completing a process, but there is a definite cut off point.
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