MID-TERM REVIEW

 

Past Biology Regents Exams with Answers!

Characteristics of Living Things

All living things must maintain homeostasis.

1. To maintain homeostasis, organisms carry out the same basic life functions: reproduction, nutrition, excretion, transport, cellular respiration, growth, synthesis and assimulation, and regulation.

A. Growth- All animals and plants grow- initially anyway

B. Nutrition- all organisms obtain food from the environment

Autotrophs (plants) make their own food

Heterotrophs (animals) must eat other organisms for food

C. Cellular Respiration: Organisms get energy by breaking the bonds of sugar molecules.

D. Transport: Food and oxygen is transported through the body

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

F. Reproduction: Making offspring (Not required for the "survival" of one individual organism).

G. Excretion: Metabolic waste is removed from the body

H. Synthesis and assimulation: Making compounds and taking them into your body!

2. All life processes make up an organism’s metabolism. Metabolism is all the chemical reactions that are required to sustain life.
3. Failure to maintain homeostasis causes disease and death.

 

SAFETY IN THE LAB

  • Don't point heating test tubes towards your face- it could explode in your face
  • Don't put a stopper on heating test tubes- it could explode in your face
  • Wear safety goggles- glass or dangerous chemicals could explode in your face
  • No open toe shoes- glass or dangerous chemicals could fall on your toes
  • Tie back long hair- your hair could catch on fire or dip into unpleasant fluids

 

EXPERIMENTATION

A. Hypothesis: A new concept that is tested by the scientific method. Must be a detailed statement.

B. Dependent Variable is the thing that will change DEPENDING on the independent variable. For instance, my weight DEPENDS on how much I eat. The dependent variable is my weight.

C. Independent Variable is the factor that changes (often gradually) in an experiment independent of anything else that is going on in the experiment. The independent variable is how much I eat.

D. Control Group is the group that is studied under the normal conditions without any variables. It is important in order to draw valid conclusions from an experiment.

E. Experimental Group is the group that has ONE CHANGE or variable from the control group.

F. 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.

G. How can you make an experiment more valid?

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

H. Parts of the microscope and magnification- know where to find them on a diagram

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 let into the microscope

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)

I. When you look at an object under a microscope:

1. Increasing magnification reduces the field of view. (Your field of vision is larger under low power but you see less of it)
2. Increasing the magnification reduces the amount of light. (Field darkens)
3. To move an object under magnification- move the object with the knobs on the stage the OPPOSITE direction that you want it to go.
4. Remember: When you switch from low to high power, the area you see is darker and smaller.

J. Additional Laboratory Techniques

  1. Gel Electrophoresis- A process that is used to compare fragments of DNA by using electricity.
  2. Chromatography- A process of separating solutions of chemicals based on how fast the differently sized molecules travel through special filter paper.
  3. Centrifuge- Used to separate the particles based on their density Heavy particles are on the bottom- lighter are on the top.
  4. Indicators- Compounds that show chemical properties usually by color change
  5. Stains- A substance that makes parts of a cell structure more visible.

 

EVOLUTION

Taxonomy

  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. Ex. Canis rufus and canis lupus familiaris
  5. The major taxons from broadest to most specific are: Kingdom, Phylum, Class, Order, Family, Genus, Species. The higher up the taxon, the more organisms it contains.

Evidence of Evolution

  1. Evolutionists derive the support for their theories through genetics, fossil record and radioactive dating.
  2. Sedimentary rock is important to the study of evolution because it IS the rock type that has fossils.
  3. Structures are homologous if structures such as bones look really similar between two species. This means the two organisms share a common ancestor. ex. whale flipper and human arm.
  4. Cladograms indicate whether two species have a common ancestor if they have a common "root" of the tree.
  5. Organisms that are closely related will have many things in common such as their enzymes.

Modern Evolution

  1. Adaptions or "fitness" is what selectively drives evolution. A species must reproduce in order to evolve.
  2. Geographic isolation results in the formation of a new species because the isolated species only have a segment of the total original gene pool so over time they will become a different organism.
  3. The three steps of natural selection are a population of species have a variety of genes, they have more babies than survive, the competition for survival favors the individual with the best characteristics (this can include some genetic behaviors too!)
  4. The peppermoth is a modern example of natural selection because albino moths died out from the original population when they were easily seen in the polluted environment and therefore over hunted by birds.
  5. Punctuated equilibrium when viewed on a time graph shows jagged/quick changes in species while the gradual equilibrium is a more gentle change.
  6. Species do not evolve just because they NEED a trait. (Lamark)
  7. Modern evolutionary theory is highly advanced now because of our understanding of genetics.


BIOCHEMISTRY

    1. The most common elements in living things are N, H, C and O.

    2. Elements that MUST be in organic compounds are C and H.

    3. Carbohydrates are sugars and starches. All carbohydrates are made from simple sugars- monosaccharides (like glucose) and they supply energy. Polysaccharides are starches.

    4. Lipids store energy and include fats, oils and waxes. They are made from fatty acids and glycerol.

    5. The building blocks of proteins are amino acids. Amino acids are joined together by a peptide bond.

    6. Proteins make enzymes, hormones, antibodies, and tons of cell structures.

    7. An enzyme helps a chemical reaction go faster and with less energy.

    8. Enzymes are named by what ever they are working on and then adding an 'ase to the end. For instance maltase works on maltose.

    9. The Lock and Key model refers to the necessity of an enzyme to fit perfectly with the substrate otherwise the reaction will not take place. It is the shape of an enzymes that allows them to function or not.

    10. The shape of protein molecules are caused by the amino acid order.

    11. When enzymes are in extremely hot or cold temperatures they denature or lose their shape. They no longer work.

    12. Really high or low pH's can denature an enzyme too.

    13. Increasing the concentration of the substrate speeds up the rate of enzyme action.

    14. The presence of an enzyme lowers the activation energy needed for a chemical reaction.

    15. Acids have a pH below 7 while bases are above 7.

    16. In a chemical equation, the reactants are the beginning items and the products are what you end up with.

    17. Hydrolysis is when you ADD water to break compounds apart, dehydration synthesis is when you take OUT water to connect compounds together.

     

CELLS

1. Cells are the basic unit of structure and function of all living organisms. All living things (except viruses) are made of cells.

2. The cell theory is that all living things are made of cells, cells come from preexisting cells and cells metabolize.

3. Plant cells have cell wall, chloroplasts and huge vacuoles and animal cells have centrioles.

4. cell (plasma) membrane- to allow materials such as oxygen in and out of cell

5. cell wall- for protection and structure

6. nucleus- stores the DNA: genetic information

7. chloroplast- site of photosynthesis

8. cytoplasm- the jelly like substance that holds organelles in place inside a cell

9. ribosome- makes proteins

10. vacuole- stores water and toxins

11. mitochondria- makes energy- ATP for the cell

 

The fluid mosaic model of the cell membrane contains two layers of lipids broken occasionally by a protein molecule.

 

What You Absolutely Need to Know to Pass the Regents