BIOLOGY FINAL REVIEW

Past Biology Regents Exams with Answers!

Characteristics of Living Things

A. All living things must maintain homeostasis.

1. To maintain homeostasis, organisms carry out the same basic life functions: nutrition, excretion, transport, respiration, growth, synthesis and regulation. Know these terms!
2. All life processes make up an organism’s metabolism.
3. Failure to maintain homeostasis causes disease and death.

B. Nutrition:

1. Autotrophs make their own food, while heterotrophs eat other organisms.
2. Photosynthesis is carried out by plants, algea and blue-green bacteria (autotrophs). It takes the radiant energy of the sun and puts it in the bonds of sugar molecules. Photosynthesis occurs mostly in the chloroplast of plant cells.

  • Plants have stomates, small holes in their leaves that let them exchange the gasses used in photosynthesis.
  • Guard cells open and close the stomates.

C. Respiration: Organisms get energy by breaking the bonds of sugar molecules. The released energy is used to make a molecule of ATP, which gives all organisms their energy.

1. Aerobic respiration requires oxygen, and yields more ATP (energy) for a molecule of sugar than anaerobic (no oxygen) respiration.
2. When humans are forced to get energy from anaerobic (no oxygen) respiration, we produce lactic acid that damages muscles (“the burn” you feel during exercise).
3. Photosynthesis and Aerobic Respiration are opposite reactions! They are also important in cycling oxygen, carbon, hydrogen and water through the environment.

D. Transport:

1. Diffusion: movement of molecules from high concentrations to low concentrations. Requires no energy (passive transport).
2. Active Transport requires the use of energy, usually moving molecules from a low concentration to a high concentration (against the flow of diffusion).
3. Osmosis is the diffusion of water into or out of the cell. If water diffuses into the cell, the cell swells (get larger) and may burst. If it loses water (being put in salt water for example) it will shrivel up.

E. Regulation: coordination and control of other life functions.

1. A stimulus is a change in the environment that you respond to.
2. A neuron is a nerve cell.
3. An impulse is the electrical signal carried by the nerves. Neurotransmitters are chemicals that help carry the impulse.
4. A hormone is a chemical signal secreted by different glands in the body. Examples of hormones include insulin, adrenaline, testosterone and estrogen
5. Receptor molecules are proteins on the surface of the cell membrane that receive signals from the nervous and endocrine system. These are needed for your cells to communicate and work together.

F. Chemistry

1. The most common elements in living things are (in order) Carbon, Hydrogen, Oxygen and Nitrogen (CHON).
2. Organic Compoundshave Carbon AND Hydrogen (ex: C6H12O6 is organic, H2O, CO2, and NO3 are not). Organic molecules are also larger than inorganic molecules.
3. Carbohydrates are sugars and starches. All carbohydrates are made from simple sugars (like glucose) and they supply energy.
4. Lipids store energy and include fats, oils and waxes. They are made from fatty acids and glycerol.
5. Proteins are made from amino acids. Proteins also make hormones and many body and cell structures, so as far as your body is concerned, proteins are by far the most important of these three organic molecules.

a. It is the SHAPE of proteins and how they fit together that determines what proteins can do.
b. Four specific jobs of proteins:

1) make enzymes
2) make receptor molecules on the cell membrane. These are used to receive chemical messages (like hormones).
3) make antibodies
4) make hormones

c. Enzymes are catalysts– they affect the rates of chemical reactions.

1) lock and key model– one type of enzyme fits one type of molecule. Change its shape and the enzyme will no longer work.
2) very high temperatures cause proteins and enzymes to lose their shape so that they no longer work properly. This is why high fevers are dangerous.

6. pH: The pH scale measure the strengths of acids and bases. A low pH (0-6.9) is a acid, a high pH (7.1-14) is a base, and 7 is neutral (water).

G. Cells- Cells are the basic unit of life. All living things (except viruses) are made of cells.

1. You must know the cell theory (All living things are made of cells. Cells come from preexisting cells).
2. You must know the differences between plant and animal cells- cell wall, chloroplasts.
3. You must know the following organelles and their functions: cell membrane, cell wall, nucleus, chloroplast, cytoplasm, ribosome, vacuole, mitochondria
4. The cell membrane is made of lipids and proteins.

  • The cell membrane is needed to control movement into and out of the cell
  • It shows selective permeability – that is only some molecules can pass through it (typically small molecules like water and oxygen).
  • Large molecules (like starch or protein) need to be moved by active transport.

5. The plants cell wall is mostly for protection.

H. Classification-

1. Organisms are classified mostly by evolutionary history. Those with common ancestors are grouped together.
2. Kingdoms are large groups of related organisms (fungi, bacteria, protists, animals, plants).
3. A species is able to successfully reproduce amongst its members.
4. A scientific name is made up of an organism’s Genus and species. The most similar genes are found between animals of the same Genus.

Maintaining Homeostasis in the Human Body:

A. Organization:

1. Cells are specialized into tissues.

a. Tissues are groups of cells specialized to do certain jobs. Examples of tissues include muscle tissue and nerve tissue.
b. Specialization or differentiation occurs because only some genes in the nucleus of a cell are “turned on”. Almost every cells has a complete set of genes, but on those needed for the cells particular job are active.

  • So while a red blood cell has all the genetic information needed to make nerves cells, bone cells and skin cells, all those genes are turned off, and only the red blood cell genes are turned on.

2. Tissues work together to form organs (heart, lungs, kidney).
3. Organs work together in organ systems (digestive system, nervous system, etc).

B. Digestive System:

1. Food is broken down so that it is small enough to enter the body tissues/cells.
2. The digestive system is a one way passage through the body that includes the mouth, stomach and intestines.
3. Food is moved through the digestive system by muscular contractions (peristalsis) in the esophagus, stomach and small intestines.
4. Food is broken down mechanically and chemically (enzymes and low pH).
5. Undigested food is eliminated as solid waste. This is not excretion.

C. Transport/Circulatory System.

1. Moves material (water, nutrients, hormones, wastes) through the body.
2. Red blood cells carry oxygen. White blood cells fight disease.
3. Plasma is the fluid of the blood. It transports everything except oxygen.
4. Platelets clot the blood.

D. Immune System:

1. The job of the immune system is to protect the body against pathogens.

a. Types of pathogens include viruses, bacteria, and parasites.

2. White Blood Cells are the main components of the immune system. Different white blood cells have different roles.
3. Antigens cause an immune response. Antibodies are proteins made by white blood cells to attack antigens. Each antibody attacks a specific antigen as determined by its shape.
4. Be able to explain why your body’s immune system rejects organ transplants.
5. Blood type O is a universal donor; type AB is the universal acceptor.
6. A vaccineis an injection of a dead or weakened pathogen. This causes the body to make antibodies against that pathogen. Vaccines only prevent diseases. They are not cures.
7. Antibiotics are drugs used to stop infections by bacteria. Antibiotics will not work against viruses.

If you don't finish your course of antibiotics (a week or two) you will breed SUPER bacteria that can genetically resist the antibiotics.

E. Respiratory System:

1. Physical respiration (breathing) provides oxygen needed for chemical respiration (which releases energy from sugar).
2. The diaphragm is the muscle that allows breathing to occur.
3. You breathe faster when CO2 builds up in the blood (not when you need oxygen).
4. The alveoli are very important because it is here that the oxygen enters the blood and CO2 leaves. The alveoli took like microscopic sacs surrounded by capillaries.

F. Excretory System:

5. Removes metabolic waste from your body.
6. Your body excretes salt, water, urea and CO2.
7. Lungs excrete CO2 and water and the skin excretes sweat.
8. The kidneys filter waste from blood and reabsorb nutrients.
9. The liver filters toxins and dead red blood cells from the blood.

G. Skeletal Muscle System

1. Know the function of bones, bone marrow, cartilage, tendons and ligaments.
2. Muscles only pull and must work in pairs.

H. The Nervous System

1. The nervous system regulates your body along with the endocrine system.
2. Know the three parts of the brain and what they do (cerebrum, cerebellum, medulla).
3. The spinal cord controls reflexes and brings impulses from the nerves to the brain.
4. Neurotransmitters are secreted between the neurons to transmit messages.

I. Endocrine System:

1. Regulates body along with nervous system. Slower but with longer lasting effects.
2. The pancreas makes insulin and glucagon which control blood sugar. (This is an example of a feedback mechanism).
3. Adrenal glands make adrenalinewhen the body is under stress.
4. Testosterone (male), estrogen and progesterone (female) are the sex hormones.
5. Hormone levels are controlled by negative feedback.

J. Interaction between Systems:

Be able to explain how different systems of the body work together to maintain homeostasis.

  • Nutrients from the digestive system are transported to cells by the circulatory system.
  • Wastes from respiration are removed by the excretory system.
  • The nervous and endocrine systems work together to control the body

K. Diseases and Disorders:

1. Be familiar with different diseases and disorders, what causes them, and how they may affect the body. Typically the exam will ask you to name a disease and how its disrupts homeostasis.

2. Diseases and disorders include: Heart attack, stroke, cancer, Down’s syndrome, diabetes, cystic fibrosis, sickle cell anemia, diarrhea, ulcers, AIDS, goiter, scurvy, rabies, meningitis, pneumonia, asthma, bronchitis, appendicitis, cold, flu

3. Causes of diseases (Pathogens):

a. viruses (AIDS, cold, flu, chicken pox)
b. bacteria (strep throat, food poisoning, syphilis)
c. fungus (athlete’s foot, ringworm)
d. parasites (tapeworm, leeches)
e. genetic disorders (Down’s Syndrome, sickle cell, cystic fibrosis)
f. environmental toxins (lead poisoning, radiation)
g. poor nutrition (Scurvy, goiter)
h. organ malfunction (heart attack, diabetes)

Evolution

A. Basically states that modern species evolved from earlier, different species and share a common ancestor (the same earlier species). The less differientiation between two organisms the more recently they evolved apart.

B. Charles Darwin proposed that natural selection is the mechanism that causes species to change. The basic steps in natural selection are:

1. Overproduction of offspring with a variation of genes.
2. Competition for limited resources.
3. Survival and reproduction OR death.

C. Organisms that are better adapted to their environment and able to reproduce successfully are considered “fit”.

  • Unfit organisms die, and their traits are eventually removed from the gene pool.
  • Evolutionary fitness has nothing to do with physical fitness. Stronger is not always better.

D. Evolution is usually driven by a change in the environment. The more the environmenta changes, the more the species have to adapt... or die!

E. To evolve, variations must exist in a species BEFORE the environment changes. They do not get a trait just because it is needed. Lamarck misunderstood and thought that the needs of an organism created a change in the organism!

F. Variations exist primarily as the result of sexual reproduction and mutation.

G. Species with more variation are better able to survive environmental changes.

H. Gradualismis a theory that says change occurs slowly. Punctuated equilibrium is a theory that says evolution happens in quick spurts.

I. Creation of new species usually requires geographic isolation which eventually results in reproductive isolation.

J. Evidence in support of evolution comes from the fields of geology (fossil record and radioactive dating), genetics, biochemistry, anatomy and embryology (among others).

 

GENETICS

A. Humans have 46 chromosomes, or 23 homologous pairs.

B. Chromosome pairs carry alleles for the same trait.

  • We all have two alleles for each gene- one from each parent
    • One on each member of the homologous pair.

C. While genes determine our traits, the environment can affect expression of genes.

D. Each chromosome has hundreds or thousands of genes.

  • Each gene codes for a particular protein (1 gene=1 protein).

E. DNA is made of 4 bases: ATCG.

  • A three letter codon represents a specific amino acid.
    • These amino acids are assembles into proteins.

F. Base pairs: A-T, C-G (in RNA, A-U and C-G)

G. RNA carries the genetic code to ribosomes. The ribosomes then synthesize protein.

H. Changes to DNA are called mutations. They can only be passed on if they occur in reproductive cells (sperm or egg).

I. All cells in the body contain the same genes.

  • Only some of these genes are turned on and others are silent.

J. Selective breeding produces animals and plants with desired traits (disease resistance, larger fruit, more meat or milk, specific colors).

K. Genetic engineering or gene splicing inserts genes of one organism into the genes of another.

  • Enzymes are used to cut and copy the DNA segments.
  • Bacteria are often used.

Reproduction

A. Asexual reproduction:

1. Advantages: faster, easier
2. Disadvantage: no variety. Offspring are the same as parent.

B. Sexual reproduction:

1. Advantage: variety
2. Disadvantage: more time, effort and risk.

C. Mitosis

1. Asexual
2. One division => two identical, diploid (2n) cells.
3. Chromosome number in the daughter cells is the same as in the parent cell.
4. Large organisms use mitosis for growth and healing. Simple organisms use it to reproduce.

D. Meiosis

1. Sexual reproduction
2. One cell divides twice to make four DIFFERENT cells.
3. All 4 cells are haploid (n) meaning they have half the number of chromosomes found in the parent cell.
4. Makes gametes (sex cells). In humans 4 sperm cells or 1 egg and three polar bodies are produced each time meiosis occurs.
5. Separates pairs of homologous chromosomes so that offspring get one chromosome of each pair from a different parent.

E. Fertilization occurs in the fallopian tube. A fertilized egg is called a zygote and has a normal number of chromosomes (2n).

F. The fetus develops in the uterus. Cells divide without becoming larger (cleavage). After a few days, cells begin to differentiate – that is they start to form different types of cells (nerve, skin, bone, etc). At this stage the embryo is very vulnerable to alcohol, drugs, etc because the important organs and systems are just starting to develop.

 

Ecology: This is the most important part of the test!!!

A. Understand how organisms interact with their environment (food chanis and webs, nutrient cycles). Note: the arrow points into the mouth of the consumer!

B. Energy is needed to keep an ecosystem going. The energy comes from the sun and is made usable by producers (plants and other autotrophs)

C. Energy is passed on to other organisms in the form of food. Since all organisms must use energy for their own needs, most energy is lost before it can be passed to the next step in the food chain. As a result, organisms high on the food chain have less energy available to them and must have smaller populations.

D. Environmental factors (air, water, light, temperature, pH, food, predators etc) determine which organisms can live in an ecosystem and how large the population can get. Biotic is living and abiotic is non-living.

1. The maximum size of a population is called the carrying capacity.

E. There are many roles in an ecosystem (niche), but competition between species usually results in only one species occupying a niche at any one time. Often, organisms with similar needs will divide resources to reduce competition (ex: birds eat insects during the day, bats eat them at night).

F. Know the basic processes of ecological succession- bare fields turn into grass-shrubs-trees

G. Human action (development, industrialization, pollution, farming, over hunting, overgrazing, clear cutting, introduction of foreign species, soil erosion) often has negative consequences for the ecosystem (and humans too).

H. The negative effects humans have had on the environment are all mostly due to the increasing human population.

I. Biodiversity refers to the variety of life on earth. As habitats are lost and species become extinct, biodiversity is reduced. This is bad because

1) ecosystems with low diversity take longer to recover from environmental changes

2) we use organisms for many things such as food and medicine; by reducing biodiversity we are losing potentially valuable resources.

J. Actions being taken by humans to reduce or repair damage to the environment include:

1. Recycling wastes
2. Conserving available resources
3. Using cleaner resources (ex: solar over fossil fuels)
4. protection of habitats and endangered species
5. use of biological controls instead of pesticides and herbicides
6. Farming native plants (ex: cocoa in the rainforest)
7. Planting trees to replace those cut down.
8. Rotating crops or planting cover crops to reduce soil loss.

K. Know the following terms: producer, consumer, omnivore, herbivore, carnivore, predator, parasite, host, habitat, niche, population, community, ecosystem, biosphere, pollution, renewable resource

L. For each of the following ecological problems, you should be able to identify the specific cause, their negative effects on the environment, and a way that people are trying to fix the problem:

1. acid rain
2. loss of habitat (ex: deforestation)
3. loss of diversity
4. global warming
5. loss of ozone layer
6. introduced species
7. industrialization

 

EXPERIMENTATION

A. Independent Variable is the one thing that “I change” to test my hypothesis.

B. Control Group is the group that is studied under the normal conditions. It is important in order to draw valid conclusions from an experiment.

C. Experimental Group is the group that is identical to the control group with the ONE CHANGE or difference (the Independent Variable).

D. Organizing Data

Where does the Independent Variable go on a data table? What about the Dependent

E. Labeling a graph:

1.Title the graph (The affect of _____ on _______.)
2. Label the X and Y axis.
3. Determine a proper scale for X and Y axis.
4. Set up a key or legend if necessary.

F. How can you make an experiment more valid?

1. Repeat the experiment
2. Increase the number of specimens or trials.
3. Peer review

G. Parts of the microscope and magnification:

1. Eyepiece: the part that you look through (closest to the eye) usually 10x
2. Objective Lens: the magnifying part closest to the slide (high power=usually 40x; low power=usually 10x)
3. Fine Adjustment Knob: used to focus on low & high power
4. Course Adjustment Knob: used to focus only on low power
5. Stage: where the slide is placed
6. Stage Clips: hold the slide in place
7. Diaphragm: controls the amount of light used

How to calculate total magnification: if a microscope has a 10X eyepiece, and 10X and 40X objectives.
Total Magnification on low power: 10 X 10 = 100X (it looks 100 times bigger than real life)
Total magnification on high power: 10 X 40 = 400X (it looks 400 times bigger than real life)

H. If you looked at the letter under a microscope, what would it look like?

1. Mirror image and flipped up side down.
2. Increasing magnification reduces the field. (Larger image but you see less of it)
3. Increasing the magnification reduces the amount of light. (Field darkens)

I. How to make a wet mount slide:

Put the cells on the center of a slide, put a drop of water with a dropper onto the cells (do not touch the cells); lower a cover slip slowly at an angle (to reduce the number of air bubbles)

J. How to put stain on a slide without lifting the cover slip:

Put a drop of the stain onto the edge of the cover slip; place a paper towel on the edge of the other side of the cover slip, the paper towel will pull the water from under the cover slip, and in turn pull the stain onto the cells.

K. Laboratory Tests to Know:

1. Paper Chromatography is a laboratory technique that is used to separate different molecules from one another. (Separation of compounds in a solution by size and color).
2. Gel electrophoresis - separation of DNA using electrical current by size
3. Indicators for pH, Glucose, Starch – color or state change indicating the presence of a particular substance.

L. Dichotomous Keys: are tools to help in the classification of organisms.

 

Review of the Four NY State Labs