Name: _______________________________________________ Date: ______________ Period: ______
UNIT 2 Review Sheet
Enzymes​:
Videos​: ​Enzymes​ ​Video​ & ​Advanced ENZYMES Video
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Enzymes (also known as catalysts) are proteins that speed up the rate of chemical reactions.
Enzymes are highly specific meaning that their shape is
very specific and determines the enzyme’s function.
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Temperature can change the rate of reaction.
Enzymes function best a specific temperatures & pH values (these are called optimal
temperature & optimal pH)
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Temperature and pH can change the shape of an enzyme. If temperatures or pH are too
extreme (very high temperature or very strong acid or base) permanent change of shape occurs
this is called denaturing.
Change in enzyme shape leads to change in enzyme function and it will no longer work.
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Name: _______________________________________________ Date: ______________ Period: ______
UNIT 2 Review Sheet
Diffusion
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Video: ​Diffusion Demo Video
Diffusion is the movement of molecules from a high concentration to a low concentration. Does
not require energy.
Diffusion Through a Membrane State Lab (Part 1):
Important Terms
Diffusion
Selectively permeable
Indicators
Dialysis tubing
Starch
Glucose
Starch indicator (Iodine)
Glucose indicator (Benedict’s Solution)
Key Points I
1. Molecules tend to move from high to low concentration without the use of energy (​diffusion​).
2. Membranes may allow some molecules to pass through while not allowing others (​selectively
permeable​).
3. Indicators​ are used to show the presence of certain kinds of molecules.
Procedure I
1. A model cell is made using a plastic membrane (usually ​dialysis tubing​) containing ​starch​ and
glucose.​ The bag is sealed with string.
2. Starch indicator​ ​(iodine) is placed in solution outside the ‘cell’.
3. Because of the differences in concentration, starch indicator diffuses in and glucose diffuses out.
Starch ‘wants’ to diffuse out, but cannot because the molecule is too large to pass through the
membrane.
4. Starch (milky white) + starch indicator (brown) = blue-black color
5. The inside of the bag turns blue-black
while the outside stays brown, proving that
indicator went in, but starch did not leave.
6. ​Glucose indicator​ (blue) + glucose (clear) +
HEAT = green, brown, red, or orange
7. Testing the fluid outside the ‘cell’ shows
glucose has left. This is tested by placing
fluid from outside into a test tube, adding
indicator solution, and heating the mixture.
8. You may prove that #6 is true by testing (heating) indicator alone and also testing indicator + starch.
Both of these ​controls​ result in a blue color (no change).
Analysis I
1. Glucose and starch indicator may pass through the membrane. Starch may not. This is because
starch is a much larger molecule than glucose or starch indicator.
2. This shows the importance of breaking down large molecules inside the digestive system in
order for nutrients to enter the bloodstream.
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Name: _______________________________________________ Date: ______________ Period: ______
UNIT 2 Review Sheet
Organic Compounds:
​Organic Compounds (aka biomolecules) Video
​Biological Molecules Crash Course Video
❖ Summary Notes: Basic Chemistry
Element​: one kind of atom (found on the periodic table)
Compound​: two or more atoms bonded together
[On the test, these can be referred to by their names or they may be called substances or molecules.]
Organic Macromolecules:
There are 3 classes of organic macromolecules.
1. Carbohydrates:
● Sugars:
-​Uses​: quick energy, energy used for cellular respiration
Structure: C, H, O sugars are small molecules
-​Most Common​: glucose, fructose, sucrose
● Starches:
-​Uses​: longer term energy release, stores sugars
-​Structure​: made of many simple sugars, C,H,O and are large molecules
*Should make up the majority of our daily diet, focusing on fruits and vegetables first, then on
grains (like rice, breads, pastas, and cereals).
2. Lipids:
-​Uses​ (why does our body need them): stores energy in the bonds of the large molecules, used
for insulation and protection of internal organs, very important to brain function, especially in infants
-​Structure​: very large molecule made of C, H, and O
*Should make up the lowest percentage in our daily diets (what we eat).
3. Proteins:
-Uses​: all structures in our bodies are made of proteins, used for energy ONLY IF there is no
sugars, starches, or lipids available
-​Structure​: proteins are made of amino acids, and contain C,H,O, and N (can include other
elements, based on the amino groups attached), proteins fold in on themselves making different shapes
and those shapes will determine the function of that protein or the trait that is expressed proteins are
usually large molecules
*Proteins should make up the next lowest percentage in our daily diets.
*Important Proteins to Remember: hemoglobin, receptor molecules, insulin, actin, myosin
Inorganic Molecules
Some examples:
-Calcium (Ca): used for strong bones and teeth
-Iron (Fe): attaches to hemoglobin in red blood cells to help transport oxygen
-Potassium (K): important for metabolism and nervous system function
-Vitamins: many different vitamins, are responsible aids in all metabolic processes
-Salt (NaCl): helps to maintain water balance in the body as well as nervous system function
-Water (H​2​O): makes up most of our bodies
-Oxygen (O​2​): needed for cellular respiration
-Carbon Dioxide (CO​2​): metabolic waste in heterotrophs but used for photosynthesis in
autotrophs
-Ammonia (NH​3​): metabolic waste
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Name: _______________________________________________ Date: ______________ Period: ______
UNIT 2 Review Sheet
Cellular Respiration & Photosynthesis:
Photosynthesis Video
Cellular Respiration Video
Crash Course Biology CELL RESPIRATION Video
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