AP Biology Fall 2016 Final Exam

Study Guide Answers

Chapter 2

1

• Carbon

• Hydrogen

• Nitrogen

• Oxygen

2

• Trace elements are elements your body needs only in very small amounts.

• Ex: Fe, Zn, Co, Cu, F2, I2, Mn,

3

• Atomic number = proton number

• Atomic mass = protons + neutrons

4

• Isotope = two elements with the same atomic number, but differing atomic masses due to neutron numbers.

– Ex: C12 & C14

5

• Be able to do this.

• Ex: An element has 66 neutrons and has 49 electrons. What’s the atomic number?

• 49

• Electrons = protons = atomic number

6

• Covalent = electrons are shared between elements.

– Polar covalent = shared unequally– Non-polar covalent = shared equally.

• Ionic = electrons are given to another element• van der Waals = momentary attractions due to

charge interactions on spinning adjacent electrons.

• Hydrogen = a type of van der Waals interaction where magnetic attraction between a hydrogen on one water molecule and the oxygen of another molecule.

7

• Electronegativity (electro(-)) represents the element’s desire to have electrons.

• The more electro(-) the atom, the more likely it is to steal an electron from another atom, creating a compound with an ionic bond.

4

• Low density ice floats on the surface of liquid water, acting as an insulator ensuring that the water below the ice never drops below freezing. This allows life to continue to exist under the ice during the winter.

• Otherwise, the ice would sink, trapping and killing all of the organisms, disrupting food chains and decreasing oxygen levels leading to further death.

IT’S A TRAP!!!

Chapter 4

1

• Carbon

2 & 3

• See following slides…

Fig. 4-10c

STRUCTURE

EXAMPLE

NAME OFCOMPOUND

FUNCTIONALPROPERTIES

Carboxyl

Acetic acid, which gives vinegar its sour taste

Carboxylic acids, or organic acids

Has acidic propertiesbecause the covalent bond between oxygen and hydrogen is so polar; for example,

Found in cells in the ionized form with a charge of 1– and called a carboxylate ion (here, specifically, the acetate ion).

Acetic acid Acetate ion

Fig. 4-10d

STRUCTURE

EXAMPLE

NAME OFCOMPOUND

FUNCTIONALPROPERTIES

Amino

Because it also has a carboxyl group, glycine is both an amine anda carboxylic acid; compounds with both groups are called amino acids.

Amines

Acts as a base; can pick up an H+ from the surrounding solution (water, in living organisms).

Ionized, with a charge of 1+, under cellular conditions.

(ionized)(nonionized)

Glycine

Fig. 4-10e

STRUCTURE

EXAMPLE

NAME OFCOMPOUND

FUNCTIONALPROPERTIES

Sulfhydryl

(may be written HS—)

Cysteine

Cysteine is an important sulfur-containing amino acid.

Thiols

Two sulfhydryl groups can react, forming a covalent bond. This “cross-linking” helps stabilize protein structure.

Cross-linking ofcysteines in hairproteins maintains the curliness or straightness of hair. Straight hair can be “permanently” curled by shaping it around curlers, then breakingand re-forming thecross-linking bonds.

Fig. 4-10f

STRUCTURE

EXAMPLE

NAME OFCOMPOUND

FUNCTIONALPROPERTIES

Phosphate

In addition to taking part in many important chemical reactions in cells, glycerol phosphate provides the backbone for phospholipids, the most prevalent molecules in cell membranes.

Glycerol phosphate

Organic phosphates

Contributes negative charge to the molecule of which it is a part (2– when at the end of a molecule; 1– when located internally in a chain of phosphates).

Has the potential to react with water, releasing energy.

CHAPTER 5

1

• Carbohydrates: C, H, O (1:2:1)

• Lipids: C, H, O (Not 1:2:1)

• Proteins: C, H, O, N

• Nucleic Acids: C, H, O, N, P

2

• Cellulose and chitin have β-1,4 linkages.

• Strings of glucose monomers as starch have α-1,4 linkages

3

• Plant cell walls

4

• Fungal cell walls and in the exoskeletons of certain invertebrates.

5

• Carb: monosaccharide

• Lipid: isn’t one

• Protein: amino acid

• Nucleic Acid: nucleotide

6

• Dehydration synthesis is an anabolic process that joins monomers by removal of a water molecule.

• Hydrolysis is a catabolic process that breaks down polymers by adding a water molecule.

7

• Saturated FA: Fully saturated with hydrogens; solid at room temp; usually animal fats.

• Unsaturated FA: not fully saturated with hydrogen; where hydrogen have been removed, c=c double bonds have been generated; usually plant oils…and some fish oils.

8

• Peptide bonds

9

• Hydrogen bonds

10

• Alpha helix & beta-pleated sheet

11

• A, T, C, G, U

12

• Purines: A, G

• Pyrimidines: T, C, U

CHAPTER 6

1

• Prokaryotic– Small– Unicellular– Ex: bacteria– Lack:

• Nucleus• Membrane-bound

organelles

– Have:• Cytoplasm• Cell wall• Cell membrane• Ribosomes• DNA

• Eukaryotic– Small to large– Uni to multicellular– Ex: everything but bacteria– Have:

• Cytoplasm• Cell wall• Cell membrane• Membrane-bound

organelles• DNA & nucleus

2

• 1.) Surface area to volume ratio

• 2.) Genome to volume ratio

3

• Make proteins

4

• Lysosome

– Used proteolytic enzymes

– Found in animal cells

5

• Chloroplast

• Cell Wall

• Central Vacuole

6

• Centrioles

• Lysosomes

7

• Mitochondria & chloroplasts

8

• Mitochondria & chloroplasts

9

• 9 + 2 arrangement of microtubules

CHAPTER 7

1

• Bilayer made of phospholipids, proteins, cholesterol, glycoproteins, glycolipids.

2

3

• Simple diffusion

• Osmosis

• Facilitated diffusion

• All are passive

• All move molecules down a concentration gradient.

4

• Gases

5

• glucose

6

• Sodium potassium pump is used to move Na+ & K+ across the cell membrane against their gradients.

• In nerve physiology, Na+ rushes into the cell and K+ rushed out. The Na+/K+ pump is used to repolarize the neuron by sending the ions back to where they started.

Nervous System

1

• CNS & PNS

2

• Somatic NS

3

• Autonomic NS

4

• Sympathetic & Parasympathetic

5

• Sympathetic NS

6

• A.) S

• B.) PS

• C.) PS

• D.) S

• E.) S

• F.) PS

7

• To speed up nervous conductions

8

• These gaps in the myelin sheath serve as conduction points.

• The signal jumps from node to node, speeding up conduction.

9

• Myelinated = faster & white

• Non-myelinated = slower & grey

10

• Unequal charge inside & outside the neuron.

11

• Sodium-potassium pumps

12

• During the refractory period, Na/K pumps move the ions back to their original sides, against the concentration gradient.

13.) Steps of a nerve impulse

• 1.) Resting potential

• This is the unstimulated, polarized state of the neuron (about -70 mV).

• 2.) Action Potential

• In response to a stimulus, gated ion channels in the membrane suddenly open and permit the Na+ from the outside to rush into the cell.

• As the positively charged ions rush in, the charge on the cell membrane becomes depolarized (more positive), on the inside.

13 CONTINUED

• If the stimulus is strong enough (if it is above a certain threshold level), more Na+ gates open, increasing the flow of Na+ even more.

• This results in an action potential, or complete depolarization.

• This in turn stimulates the opening of adjacent Na+ gates and the stimulus travels down the neuron.

• The action potential is all or nothing, meaning that if the stimulus fails to produce a depolarzation that exceeds the threshold potential, no action potential will result.

13 CONTINUED

• However, when the threshold potential is exceeded, complete depolarization occurs.

• 3.) Repolarization

• In response to the inflow of Na+, another ion channel opens allowing K+ to leave the cell.

• The movement of K+ out causes repolarization by restoring the original membrane polarization.

• Unlike the resting potential, however, the K+ and Na+ are now on the wrong sides.

• The K+ gates close soon after the Na+ gates close.

13 CONTINUED

• 4.) Hyperpolarization• By the time the K+ channels close, more K+ has moved

out than is necessary to to establish the original polarized potential.

• Thus the membrane becomes hyperpolarized.

13 CONTINUED

• 5.) Refractory Period• After the action potential has passed, the membrane is

in a weird state: – the membrane is polarized, but the Na+/K+ are on the wrong

sides.

• During the refractory period, the neuron will not respond to a new stimulus.

• To reestablish the original distribution of the ions, Na+/K+ pumps are used to pump Na+ out of the cell and K+ into the cell.

• Once the ions are on the proper sides, the neuron is ready for another stimulus.

14

Muscular system

1.) Steps of muscle contraction

• 1.) Action potential travels down the T-tubules and causes the S.R. to release calcium (Ca2+).

• 2.) ATP binds with myosin head forming ADP + Pi

• 3.) Ca2+ opens the binding sites on actin by binding to the troponin molecules and causing the tropomyosin to uncover the binding sites.

• 4.) Myosin heads bind to actin, forming cross-bridges.

• 5.) ADP + Pi are released resulting in the myosin heads pulling on the actin filaments and causing the sarcomere to shorten.

• 6.) Another ATP molecule attaches to the myosin heads causing the myosin heads to release from the actin and the sarcomere slides

back to original length.• 7.) Calcium releases from the actin and closes the binding sites.

2.)

• Calcium unlocks the binding sites on actin, allowing myosin cross bridges to grab the actin, initiating the contraction.

Feedback

1

Positive Feedback

• Stimulus causes a response, which reinforces the stimulus…reinforcing and intensifying the response.

• Usually bad.

• Ex: hyperventilating fainting

Negative Feedback

• Stimulus causes a response, which removes the stimulus.

• How homeostasis is maintained.

2

• A reflex arc is a negative feedback loop.

• A cramp is positive feedback.