more about biology

Question 1

Metabolism

Answer 1

all chemical reactions occurring in an organism

Question 2

Anabolism

Answer 2

chemical reactions that expend energy to make new chemical bonds

Question 3

Catabolism

Answer 3

chemical reactions that harvest energy when bonds are broken

Question 4

cofactors

Answer 4

usually metal ions, found in the active site participating in catalysis

Question 5

coenzymes

Answer 5

nonprotein organic molecules, often used as an electron donor or acceptor in a redox reaction

Question 6

Energy

Answer 6

the capacity to do work

Question 7

kinetic energy

Answer 7

the energy of motion

Question 8

potential energy

Answer 8

stored energy

Question 9

Energy can take many forms

Answer 9

mechanical electric current

heat light

Question 10

Heat energy is measured in

Answer 10

kilocalories.

Question 11

One calorie

Answer 11

= the amount of heat required to raise the temp of water by 1oC

Question 12

oxidation:

Answer 12

loss of electrons

Question 13

reduction

Answer 13

gain of electrons

Question 14

redox reactions

Answer 14

are coupled to each other

Question 15

NAD+

Answer 15

• is an electron carrier
• NAD accepts 2 electrons and 1 proton to become NADH
• the reaction is reversible

Question 16

aerobic respiration

Answer 16

final electron receptor is oxygen (O2)

Question 17

anaerobic respiration

Answer 17

final electron acceptor is an inorganic molecule (not O2)

Question 18

fermentation

Answer 18

final electron acceptor is an organic molecule

Question 19

substrate-level phosphorylation

Answer 19

transferring a phosphate directly to ADP from another molecule

Question 20

oxidative phosphorylation

Answer 20

use of ATP synthase and energy derived from a proton (H+) gradient to make ATP

Question 21

The complete oxidation of glucose proceeds in stages

Answer 21

1. glycolysis
2. pyruvate oxidation
3. Krebs cycle
4. electron transport chain & chemiosmosis

Question 22

Glycolysis

Answer 22

converts glucose to pyruvate.

• a 10-step biochemical pathway
• occurs in the cytoplasm
• 2 molecules of pyruvate are formed
• net production of 2 ATP molecules by substrate-level phosphorylation
• 2 NADH produced by the reduction of NAD+

Question 23

For glycolysis to continue, NADH must be recycled to NAD+ by either:

Answer 23

1. aerobic respiration – occurs when oxygen is available as the final electron acceptor
2. fermentation – occurs when oxygen is not available; an organic molecule is the final electron acceptor

Question 24

Pyruvate Oxidation

Answer 24

In the presence of oxygen, pyruvate is oxidized.

• occurs in the mitochondria in eukaryotes
• occurs at the plasma membrane in prokaryotes
• in mitochondria, a multienzyme complex called pyruvate dehydrogenase catalyzes the reaction

Question 25

Krebs cycle

Answer 25

oxidizes the acetyl group from pyruvate.
-occurs in the matrix of the mitochondria
-biochemical pathway of 9 steps
-first step:
acetyl group + oxaloacetate citrate
(2 carbons) (4 carbons) (6 carbons)

Question 26

The remaining steps of the Krebs cycle

Answer 26

• release 2 molecules of CO2
• reduce 3 NAD+ to 3 NADH
• reduce 1 FAD (electron carrier) to FADH2
• produce 1 ATP
• regenerate oxaloacetate

Question 27

After glycolysis, pyruvate oxidation, and the Krebs cycle, glucose has been oxidized to

Answer 27

• 6 CO2
• 4 ATP
• 10 NADH
• 2 FADH2

Question 28

electron transport chain (ETC)

Answer 28

is a series of membrane-bound electron carriers.

• embedded in the mitochondrial inner membrane
• electrons from NADH and FADH2 are transferred to complexes of the ETC
• each complex transfers the electrons to the next complex in the chain

Question 29

Electron Transport Chain

Answer 29

The higher negative charge in the matrix attracts the protons (H+) back from the intermembrane space to the matrix.

The accumulation of protons in the intermembrane space drives protons into the matrix via diffusion.

Question 30

Most protons move back to the matrix through

Answer 30

ATP synthase

Question 31

ATP synthase

Answer 31

is a membrane-bound enzyme that uses the energy of the proton gradient to synthesize ATP from ADP + Pi.

Question 32

Chloroplasts

Answer 32

organelles present in cells of plants and some other eukaryotes

- contain chlorophyll for photosynthesis
- surrounded by 2 membranes

Question 33

thylakoids

Answer 33

are membranous sacs within the inner membrane

Question 34

grana

Answer 34

are stacks of thylakoids

Question 35

Mitochondria and chloroplasts:

Answer 35

• have 2 membranes
  
  • possess DNA and ribosomes
  • are about the size of a prokaryotic cell
  • divide by a process similar to bacteria