BIOLOGY REVIEW CHAPTER ONE

 

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,
excretion, transport, respiration, growth, synthesis and assimulation, and regulation. Know these terms!
2. All life processes make up an organism’s metabolism.
3. Failure to maintain homeostasis causes disease and death.

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

B. Cellular Respiration: Organisms get energy by breaking the bonds of sugar molecules. Just eat a candy bar and you can experience that!

C. Transport: Food and oxygen is transported through the body. Otherwise only your stomach would be nourished.

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

E. Reproduction: Making offspring- at least as a species.

F. Excretion: Metabolic waste is removed from the body.

G. Synthesis and assimulation: Making compounds and adding them to yourself!

 

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 and they might explode.
  • Tie back long hair- your hair could catch on fire or dip into unpleasant fluids and your head might explode.

 

EXPERIMENTATION

A. Hypothesis: A new concept/hunch that is tested by the scientific method.

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 one thing that “I change” to test my hypothesis. It is what the dependent variable depends on- it is how much I eat in the above example.

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

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

F. Organizing Data- can use graphs, tables or diagrams

The Independent Variable goes on the X axis on a graph. The Dependent Variable goes on the Y axis.

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 given identical conditions
2. Increase the number of specimens or trials.
3. Peer review- have other people do the same experiment and agree with your results.

G. 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 4X and
10X objective lens.

  • Total Magnification on low power: 10 X 4 = 40X (it looks 40 times bigger than real life)
  • Total magnification on high power: 10 X 10 = 100X (it looks 100 times bigger than real life)

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

1. Up side down.
2. Increasing magnification reduces the field of view. (Your field of view is larger under low power but you see less detail. Under high power you see more detail of less of the object.)
3. Increasing the magnification reduces the amount of light. (Field darkens)
4. To move an object under magnification- move the object with the knobs on the stage the OPPOSITE direction that you want it to go.

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). You can place a paper towel on the edge of the cover slip to draw fluids through and out of the cover slip.

J. Additional Laboratory Techinques

  1. 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 seperate 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.