Lecture Exam 1 -- Chapter 25 Study Guide

Question 1

Define: Metabolism

Answer 1

All the chemical reactions in
the body.

Understand that catabolic and anabolic reactions need to be balanced.

Question 2

Define: Catabolism

Answer 2

breakdown - catabolic reactions are exergonic - produce more energy than they use.

Understand that catabolic and anabolic reactions need to be balanced.

Question 3

Define: Anabolism

Answer 3

build-up - anabolic reactions are endergonic - use more energy than they produce.

Understand that catabolic and anabolic reactions need to be balanced.

Question 4

Define: Oxidation

Answer 4

Oxidation - removal of electrons from an atom or molecule.

Understand that catabolic and anabolic reactions need to be balanced.

Question 5

Define: Reduction

Answer 5

Reduction - opposite of oxidation - addition of electrons to a molecule.

Understand that catabolic and anabolic reactions need to be balanced.

Question 6

ENERGY STORAGE –
How is energy stored in the cell?
From where in the ATP molecule is energy released?

Answer 6

Energy exchange usually takes place breaking chemical bonds (during dephosphorylation of ATP to ADP) and forming chemical bonds during phosphorylation of ADP to ATP.

Question 7

GLUCOSE –

What is normal blood glucose concentration in a fasting healthy adult?

Answer 7

Hormone system maintains glucose at highly constant level - approx. 90mg/100ml blood in a healthy individual.

Question 8

GLUCOSE –

How does the body use glucose?

Answer 8

1) *ATP production
2) Amino acid synthesis - cells can use glucose to form several of the amino acids.
3) Glycogen synthesis - when excess glucose present, liver cells (hepatocytes) & skeletal muscle fibers combine glucose molecules to form glycogen (glycogenesis).
4) Triglyceride synthesis - once glycogen storage capacity of liver and muscle filled - hepatocytes convert glycogen to glycerol & fatty acids. These are converted to fats (lipogenesis) - and stored in adipose tissue.

Question 9

GLUCOSE –

How does glucose enter cells?

Answer 9

Glucose enters GI tract and kidney tubules via secondary active transport (Na+/glucose
transporters).

Glucose enters other tissues via special glucose transporters (GluTs).

Glucose is phosphorylated inside cells and cannot leave in this form.

Question 10

CELLULAR RESPIRATION –

What does the term cellular respiration mean?

Answer 10

Cellular respiration is the term for oxidation of glucose to produce ATP.

Question 11

CELLULAR RESPIRATION –

Understand the 4 steps in cellular respiration.

Answer 11

1) Glycolysis - one glucose molecule oxidizes, 2 pyruvate molecules produced.
- Glycolysis does not require oxygen - therefore
called anaerobic cellular respiration

2) Formation of acetyl coenzyme A - prepares pyruvic acid for entry into Kreb’s cycle.
3) 2 pyruvic acid molecules produce 2 acetyl coAs, 2CO2, 2NADH and 2H+

Kreb’s cycle reaction - oxidation of acetyl coA and production of CO2, ATP, NADH, H+ and FADH2.

Step 4 - electron transport chain. This is a series of electron carriers. Electron carriers are integral membrane proteins in the inner mitochondrial membrane. Electron carriers move H+ across inner mitochondrial membrane.
Build up of H+ causes a concentration and electrochemical gradient resulting in generation of potential energy.

This potential energy used to synthesize ATP catalyzed by
enzyme called ATP synthase.

Question 12

CELLULAR RESPIRATION –

Where in the mitochondria do the various steps of cellular respiration take place?

Answer 12

Glycolysis (phase 1) takes place in the cytoplasm; the Krebs cycle, or citric acid cycle (phase 2), takes place throughout the mitochondrion, and electron transport phosphorylation takes place in the inner membrane of the mitochondrion, in the folds known as the cristae.

Question 13

CELLULAR RESPIRATION –

How much ATP, water and carbon dioxide are generated from one molecule of glucose?

Answer 13

6 CO2, 6 H2O, 36 or 38 ATP

Question 14

GLUCOSE STORAGE –

How is glucose stored in the liver and skeletal muscle?

Answer 14

Glucose not needed for ATP generation used for storage.

2 methods:
Glycogenesis - production of glycogen in liver.

Conversion to glycerol and fatty acids in liver followed by lipid production (lipogenesis) in adipose tissue.

Question 15

GLUCOSE STORAGE –

How is glucose processed in the liver for storage in adipose tissue?

Answer 15

Conversion to glycerol and fatty acids in liver
followed by lipid production (lipogenesis) in
adipose tissue.

Question 16

GLUCOSE RELEASE –

When needed for energy, how is stored glucose released?

Answer 16

When stored glucose needed:
1) May be released by breakdown of
glycogen - glycogenolysis.
2) May be formed from proteins and fats -
gluconeogenesis.

Question 17

GLUCOSE RELEASE –

Define: glycolysis

Answer 17

Glycolysis - one glucose molecule oxidizes, 2 pyruvate molecules produced.
- Glycolysis does not require oxygen - therefore called anaerobic cellular respiration

Question 18

GLUCOSE RELEASE –

Define: glycogenesis

Answer 18

production of glycogen in liver

Question 19

GLUCOSE RELEASE –

Define: glycogenolysis

Answer 19

releasing glucose by breakdown of glycogen

Question 20

GLUCOSE RELEASE –

Define: gluconeogenesis

Answer 20

Forming glucose from proteins and fats

Question 21

LIPID TRANSPORT –

What are the components of a lipoprotein?

Answer 21

Lipoproteins consist of an outer core of proteins, phospholipids and cholesterol and an inner core of triglycerides.

Proteins in outer core of lipoproteins are called apoproteins.

Question 22

LIPID TRANSPORT –

What are the protein components of a lipoprotein called?

Answer 22

apoproteins

Question 23

LIPID TRANSPORT –
Name 4 classes of lipoproteins.
What are the functions of each type of lipoprotein?

Answer 23

Chylomicrons - discussed last week
VLDL’s (very low density lipoproteins)
LDLs (low density lipoproteins)
HDLs (high density lipoproteins)

Question 24

LIPID TRANSPORT –

Which type of lipoprotein deposits in the arteries and causes atherosclerosis?

Answer 24

Low density lipoproteins

Question 25

LIPID TRANSPORT –

Which type of lipoprotein is beneficial?

Answer 25

high density lipoproteins