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Unit V Review Flashcards

1
Q

Chapter 25 What is metabolism

A

All the chemical reactions that take place in an organism

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2
Q

What is cellular metabolism

A

Chemical reactions within cells, which create energy

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3
Q

What is catabolism

A

The breakdown of organic molecules

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4
Q

What is anabolism

A

Synthesis of new organic molecules

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5
Q

What are the four reasons why cells synthesize new organic components

A
  1. Maintenance and repair 2. Support growth 3. Produce secretions 4. Store nutrient reserves
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6
Q

Which fuel source is used first by a cell that has an excess of fats, carbohydrates, and proteins? Why?

A

Carbohydrates. Glucose is the most efficient energy source, as fats and proteins must first be converted to other things before they can be used. (Fats are second choice, and protein is third)

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7
Q

Which step in the catabolism of glucose takes place in the cytosol of the cell

A

Glycolysis

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8
Q

What is the difference between aerobic and anaerobic metabolism

A

Aerobic = uses O2, anaerobic = does NOT use O2 Note: Glycolysis is ANAEROBIC, while reactions inside the mitochondria are aerobic

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9
Q

What is glycolysis

A

Catabolism of one glucose (6 carbon) to two pyruvate (3 carbon). (Glucose –> Pyruvic Acid –> Pyruvate)

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10
Q

Where does glycolysis take place in the cell

A

In the cytosol

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11
Q

Why is glycolysis considered to be an anaerobic process

A

It doesn’t use oxygen

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12
Q

How many carbon, hydrogen, and oxygen atoms are found in one molecule of glucose

A

C6 H12 O6

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13
Q

How many molecules of pyruvic acid are produced from the catabolism of one glucose molecule

A

Two

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14
Q

What is pyruvate

A

At the normal pH inside cells, each pyruvic acid (C3H4O3) molecule loses a hydrogen ion and exists as a negatively charged ion (called pyruvate - C3H3O3)

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15
Q

Which atoms in a glucose molecule are “harvested” and used to drive the process that synthesizes ATP from ADP

A

Hydrogen (pyruvate = C3H3O3)

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16
Q

In order for pyruvate to enter the citric acid cycle, what gas has to be available

A

O2

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17
Q

The citric acid cycle takes place in which organelle

A

Mitochondria

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18
Q

How is acetyl-CoA produced

A

NAD and coenzyme A react with pyruvate (C3H3O3) to yield: 1x acetyl-CoA (CH3CO) 1x carbon dioxide (CO2) 1x NADH

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19
Q

What is the main function of the citric acid cycle

A

To remove hydrogen atoms from organic molecules and transfer them to coenzymes

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20
Q

What acid binds to the acetyl group carried by CoA to form citric acid

A

Oxaloacetic acid (4 carbons: C4H4O5)

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21
Q

What enzymes are responsible for “harvesting” the hydrogen atoms in the citric acid cycle

A

NAD or FAD

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22
Q

What is oxidative phosphorylation and where does it take place

A

Produced more than 90% of ATP used by bodily cells. Takes place in the ETS (electron transport system - a series of integral and peripheral proteins in the inner mitochondrial membrane)

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23
Q

What compound is a byproduct of ATP synthesis

A

The basis of oxidative phosphorylation is the formation of water, a very simple reaction: 2(H2) + O2 = 2(H2O)

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24
Q

Why is oxidative phosphorylation considered an aerobic process

A

It uses oxygen [2(H2) + O2 = 2(H2O)]

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25
Q

What is the net gain in ATP molecules from the complete catabolism of one glucose molecule

A

36 molecules of ATP: 2 from glycolysis 4 from the NADH generated in glycolysis 2 from the citric acid cycle (by means of GTP) and 28 from the ETS

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26
Q

What is gluconeogenesis

A

The synthesis of glucose from noncarbohydrate precursors, such as lactate, glycerol, or amino acids

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27
Q

What precursor molecules are used in gluconeogenesis

A

Lactate, glycerol, or amino acids Note: Fatty acids cannot be used for gluconeogenesis, because their catabolic pathways produce acetyl-CoA!

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28
Q

What is glycogen and in which two organs is it mainly stored

A

Main form of glucose storage in the body. Stored primarily in the liver (400 calories) and muscles (800-1200 calories)

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29
Q

What is glycogenesis

A

Conversion of glucose to glycogen

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30
Q

What is glycogenolysis

A

Breakdown of glycogen

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31
Q

What atoms make up lipid molecules

A

Carbon, hydrogen and oxygen

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32
Q

What are the products of triglyceride catabolism

A

Glycerol and free fatty acids (FFA)

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33
Q

What is glycerol converted to in the cytosol

A

Pyruvate

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34
Q

What is beta oxidation

A

A sequence of reactions which converts FFA to 2-carbon acetic acid fragments, which are then converted to acetyl-CoA and enter the citric acid cycle

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35
Q

How many ATP molecules are synthesized when an 18 carbon fatty acid molecule is catabolized

A

144 ATP

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36
Q

Why do cells prefer to use carbohydrates for the synthesis of ATP during periods of high energy demand

A

Lipids cannot provide ATP as quickly as carbohydrates (glucose)

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37
Q

Why can almost any organic substrate be used in lipogenesis

A

The synthesis of most types of lipids begins with acetyl-CoA, and lipids, amino acids, and carbohydrates can be converted to acetyl-CoA

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38
Q

What is the most common form in which lipids circulate through the bloodstream

A

Most lipids circulate through the bloodstream as lipoproteins

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39
Q

Which cells are major users of free fatty acids

A

Liver cells, cardiac muscle cells, skeletal muscle fibers, and many other body cells can metabolize free fatty acids

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40
Q

What are lipoproteins

A

Lipid–protein complexes that contain large insoluble glycerides and cholesterol

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41
Q

What is the major constituent of chylomicrons and what is its main function

A

About 95 percent of the weight of a chylomicron consists of triglycerides

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42
Q

What are the major constituents of Low-Density Lipoproteins (LDL) and what is its function

A

Cholesterol, phospholipids, and few triglycerides They deliver cholesterol to peripheral tissues

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43
Q

Why is LDL referred to as “bad cholesterol”

A

Because the cholesterol may wind up in arterial plaques

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44
Q

What are the major constituents of High-Density Lipoproteins (HDL) and what is its function

A

Equal amounts lipid (cholesterol and phospholipids) and protein Transports excess cholesterol from peripheral tissues back to the liver for storage or excretion in the bile

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45
Q

How many amino acids are responsible for the synthesis of the hundreds of thousands of different proteins in the human body

A

20 amino acids

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46
Q

What is transamination

A

Attaches the amino group of an amino acid to a keto acid. This transfer converts the keto acid into an amino acid that can enter the cytosol, where it can be used for protein synthesis. In the process, the original amino acid becomes a keto acid that can be broken down in the citric acid cycle.

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47
Q

What is deamination

A

Prepares an amino acid for breakdown in the citric acid cycle

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48
Q

Why is the urea cycle important for the maintenance of homeostasis

A

Deamination produces toxic ammonium ions, which are neutralized into urea in the urea cycle

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49
Q

Why is protein catabolism an impractical source for quick energy

A
  1. More difficult to break apart than carbohydrates 2. Produces toxic ammonium ions 3. Proteins are vital components of cells
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50
Q

What are essential amino acids

A

10 amino acids which must come from diet and cannot be synthesized by the body

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51
Q

What are nonessential amino acids

A

Can be synthesized by the body on-demand

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52
Q

What is the role of the liver in metabolic regulation

A

The liver is the focal point of metabolic regulation: 1. Converts many enzymes to breakdown or synthesize needed carbs/lipids/amino acids 2. Large blood supply to monitor and adjust nutrient composition 3. Large energy reserves in glycogen

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53
Q

How are lipids stored in adipose tissue

A

Triglycerides

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54
Q

What is the role of skeletal muscles in energy storage and utilization

A
  1. Muscle contains substantial glycogen reserves 2. Contractile proteins can be broken down for amino acids to use as energy
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55
Q

What is unique about the energy needs of neural tissue

A
  1. Neural tissue has no reserves of carbs, lipids or amino acids. 2. Neurons need glucose (only), and cannot break down other molecules for energy Without glucose, the CNS will fail, and the person will fall unconscious
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56
Q

What is the absorptive state

A

Following a meal, cells absorb nutrients to be used for growth, maintenance, and energy reserves

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57
Q

What is the post-absorptive state

A

Metabolic reactions are focused on maintaining blood glucose levels that meet the needs of neural tissue

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58
Q

How are ketone bodies formed

A

Byproduct of fatty acid metabolism produced in the liver

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59
Q

How do peripheral tissues utilize ketones

A

Cells in peripheral tissues absorb ketone bodies and reconvert them to acetyl-CoA for breakdown in the citric acid cycle

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60
Q

What causes ketoacidosis

A

During prolonged starvation, ketone levels rise, and eventually buffering capacities are exceeded and a dangerous drop in pH takes place

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61
Q

How does the liver stabilize blood glucose levels in the post-absorptive state

A

First by the breakdown of glycogen reserves and later by gluconeogenesis

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62
Q

What are complete proteins

A

Proteins which provide all the essential amino acids (Some foods in the dairy and protein groups—specifically, beef, fish, poultry, eggs, and milk—provide all the essential amino acids in sufficient quantities. They are said to contain complete proteins.)

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63
Q

What are incomplete proteins

A

Proteins deficient in one or more of the essential amino acids

64
Q

What is protein complementarity

A

Combining two or more foods with incomplete proteins, to form complementary proteins, can provide adequate amounts of all the essential amino acids - Beans and rice - Bread and peanut butter

65
Q

Which essential vitamin is not found in the plants that we consume

A

B12, which is only obtained from animal products

66
Q

What are minerals

A

Inorganic ions released through the dissociation of electrolytes

67
Q

List some of the important minerals in the body

A

Sodium, potassium, chloride, calcium, phosphorus, magnesium

68
Q

What are the four fat-soluble vitamins

A

A, D, E, K

69
Q

List some of the important water-soluble vitamins

A

B and C vitamins

70
Q

What is the main difference between fat-soluble and water-soluble vitamins

A

Fat-soluble vitamins can be stored in the liver and adipose tissue, and as a result normal metabolic function can continue without consuming them for several months. With water-soluble vitamins, only B12 and C are stored in significant quantities.

71
Q

What is calorimetry

A

The process of calorimetry measures the total amount of energy released when the bonds of organic molecules are broken

72
Q

What are a calorie and a kilocalorie

A

calorie (small c) - the amount of energy required to raise the temperature of 1 g of water 1 degree Celsius K-cal, or Calorie (big C) - the amount of energy needed to raise the temperature of 1 kilogram of water 1 degree Celsius

73
Q

What is the caloric value of fats, carbohydrates, and proteins in Calories per gram

A

Carbs - 4 (4.18) Proteins - 4 (4.32) Fats - 9 (9.46) ** Alcohol - 7

74
Q

What is metabolic rate

A

The sum of all the Calories being used by the various anabolic and catabolic processes taking place in your body at any given time

75
Q

What is basal metabolic rate (BMR)

A

The minimum resting energy expenditure of an awake, alert person

76
Q

What factors can influence BMR

A

These factors include age, gender, physical condition, body weight, and genetic differences Note: Energy use is proportional to oxygen consumption

77
Q

Which hormone has a strong influence on the BMR

A

Thyroid hormones (thyroxine)

78
Q

How is obesity defined

A

Body weight more than 20 percent above the ideal weight for a given individual

79
Q

How do the hormones lepton and gherkin affect appetite

A

Lepton binds to CNS neurons to influence emotion and hunger

80
Q

(Chapter 10) What is an epimysium

A

A dense layer of collagen fibers that surrounds the entire muscle

81
Q

What is a perimysium

A

Divides skeletal muscle into a series of compartments

82
Q

What is a fascicle

A

Each compartment of the muscle contains a bundle of muscle fibers (called a fascicle)

83
Q

What is an endomysium

A

Surrounds the individual skeletal muscle cells, called muscle fibers, and loosely interconnects adjacent muscle fibers

84
Q

What makes up tendons

A

At each end of the muscle, the collagen fibers of the epimysium, perimysium, and endomysium come together to form either a bundle known as a tendon (The sausage case extends past the end of the meat lol)

85
Q

How are individual muscle fibers supplied with blood and innervated by nerves

A

Within the endomysium, arterioles supply blood to a capillary network that services the individual muscle fiber

86
Q

Why are skeletal muscles multinucleated

A

The genes in these nu­clei control the production of enzymes and structural proteins required for normal muscle contraction. The more copies of these genes, the faster these proteins can be produced.

87
Q

What is the sarcolemma of a muscle fiber or muscle cell

A

The plasma membrane

88
Q

What is the sarcoplasm of the muscle fiber or muscle cell

A

The cytoplasm of a muscle fiber

89
Q

What are transverse tubules?

A

Narrow tubes whose surfaces are continuous with the sarcolemma and extend deep into the sarcoplasm. Able to conduct electrical impulses, and as a result, electrical impulses conducted by the sar­ colemma also travel along the T tubules into the cell interior

90
Q

What are myofibrils

A

Each muscle fiber contains hundreds to thousands of cylindri­cal structures called myofibrils. A myofibril is 1–2m in diameter and as long as the entire cell. Branches of the T tubules encircle each myofibril. The active shortening of myofibrils is responsible for skeletal muscle fiber contraction.

91
Q

What are myofilaments? What are the two types of contractile myofilaments in skeletal muscles

A

Myofibrils consist of bundles of protein filaments called myofilaments. 1. Thin filaments 2. Thick filaments

92
Q

What is the sarcoplasmic reticulum

A

In skeletal muscle fibers, a membrane complex called the sarcoplasmic reticulum (SR) forms a tubular network around each individual myofibril, fitting over it like lacy shirtsleeves

93
Q

What important cation that is required for muscle contraction is stored in the terminal cisternae

A

Ca2+ (calcium)

94
Q

What are sarcomeres

A

Repeating functional units of myofilaments

95
Q

What are the components of sarcomeres

A

(1) thick filaments (2) thin filaments (3) proteins that stabilize the positions of the thick and thin filaments (4) proteins that regulate the interactions be­ tween thick and thin filaments

96
Q

What causes striations in skeletal muscles

A

Differences in the size, density, and distribution of thick filaments and thin filaments

97
Q

Which myofilament chiefly occupies the A band

A

Thick filament (myosin)

98
Q

What is the M line

A

The center line of the A band. (M is for middle)

99
Q

What is the H band

A

A lighter region on either side of the M line. Contains only thick filaments.

100
Q

What is the zone of overlap

A

A dark region where thin filaments are located between the thick fila­ ments. Here three thick filaments surround each thin fila­ ment, and six thin filaments surround each thick filament

101
Q

What is the I band

A

A region of the sarcomere that contains thin fila­ ments but no thick filaments. It extends from the A band of one sarcomere to the A band of the next sarcomere

102
Q

What are Z lines

A

Bisect the I bands and mark the boundary between adjacent sarcomeres. The Z lines consist of proteins called actinins

103
Q

What four proteins are found in thin filaments

A

Actin (f-actin), nebulin, tropomyosin, troponin

104
Q

What is the function of the active sites that are present on actin molecules

A

Provide a binding site for myosin

105
Q

What is the function of tropomyosin

A

Cover actin to prevent binding of myosin and actin.

106
Q

What is the function of troponin

A

Troponin binds to incoming Ca2+ and causes tropomyosin to “roll away”, exposing actin and allowing myosin binding

107
Q

What are the components of thick filaments

A

Thick filaments are made up of 300 myosin molecules. They have a myosin tail, a hinge, and a myosin head (which attaches to actin)

108
Q

How are cross-bridges formed

A

When the myosin heads interact with thin filaments during a contraction

109
Q

In the sliding filament theory, which filaments stay put and which filaments move

A

The thick filaments in the A band stay put and the thin filaments in the I band move. The Z line approaches the A band.

110
Q

What neurotransmitter is released at the neuromuscular junction

A

ACh

111
Q

What is AChE and what is its role at the neuromuscular junction.

A

Acetylcholinesterase. Breaks down ACh at the neuromuscular junction

112
Q

What happens when an action potential arrives at the sarcoplasmic reticulum

A

It triggers the release of calcium ions (Ca2+) from the terminal cisternae

113
Q

Which filament covers the active sites on the actin filament in a resting muscle

A

Tropomyosin

114
Q

What happens when calcium ions arrive at the zone of overlap

A

Ca2+ binds to troponin

115
Q

What happens when calcium ions bind to troponin

A

Troponin pulls away tropomyosin and exposes the active sites of actin

116
Q

What happens when the active sites on the actin filament are exposed

A

Myosin heads bind to the active sites (cross bridge formation). The sarcomeres shorten and pull the ends of the muscle fibers closer together

117
Q

What causes myosin heads to detach from the active sites on the actin filament

A

When the action potential ends, tropomyosin recovers the active sites

118
Q

What factors influence the duration of muscle contractions

A
  1. Period of stimulation at the neuromuscular junction 2. Level of calcium ions in the cytosol 3. Availability of ATP
119
Q

What factors affect the tension produced by an individual muscle fiber

A
  1. The fiber’s resting length at the time of stimulation 2. The frequency of stimulation
120
Q

What is a twitch in a single muscle fiber

A

A twitch is a single stimulus–contraction–relaxation sequence in a muscle fiber

121
Q

Why is there a latent period between the arrival of a stimulus and tension generation in a muscle twitch

A

The latent period corresponds to the time needed for the conduction of an action potential and the subsequent release of calcium ions by the sarcoplasmic reticulum

122
Q

What is treppe

A

If a skeletal muscle is stimulated a second time imme­diately after the relaxation phase has ended, the resulting con­traction will develop a slightly higher maximum tension than did the first contraction. The increase in peak tension will continue over the first 30–50 stimulations.

123
Q

What causes treppe

A

The rise is thought to result from a gradual increase in the concentration of Ca2+ in the cytosol, in part because the calcium ion pumps in the SR have too little time to recapture the ions between stimulations

124
Q

What is wave summation

A

If a second stimulus arrives before the relaxation phase has ended, a second, more powerful con­ traction occurs

125
Q

What is incomplete tetanus

A

A muscle producing almost peak tension during rapid cycles of contraction and relaxation is in incomplete tetanus (tetanos, convulsive tension)

126
Q

What is complete tetanus

A

When a higher stimulation frequency eliminates the relaxation phase. Action potentials arrive so rapidly that the SR does not have time to reclaim the Ca2+.

127
Q

Why are muscle twitches not useful in the production of sustainable muscle contractions

A

A single twitch is so brief that there isn’t enough time to activate a significant per­ centage of the available cross­bridges

128
Q

What is a motor unit

A

All the muscle fibers innervated by a single motor neuron

129
Q

What is a fine motor unit

A

A small number of muscle fibers being controlled by a motor neuron

130
Q

What is a gross motor unit

A

A large number of muscle fibers being controlled by a single motor neuron

131
Q

What is recruitment

A

The smooth, but steady, increase in muscular tension pro­ duced by increasing the number of active motor units

132
Q

What is muscle tone

A

In any skeletal muscle, some motor units are always active, even when the entire muscle is not contracting. Their contrac­ tions do not produce enough tension to cause movement, but they do tense and firm the muscle.

133
Q

What is an isotonic contraction

A

Tension increases and the skeletal muscle’s length changes. There are two types of isotonic contractions: concentric and eccentric

134
Q

What is a concentric contraction

A

The muscle tension exceeds the load and the muscle shortens

135
Q

What is an eccentric contraction

A

The peak tension developed is less than the load, and the muscle elongates due to the contrac­ tion of another muscle or the pull of gravity

136
Q

What is an isometric contraction

A

The muscle as a whole does not change length, and the tension produced never exceeds the load

137
Q

What are the three factors that play a role in returning a contracted muscle to its original length

A

Elastic forces, opposing muscle contractions, gravity

138
Q

What intensity and duration of physical activity can be sustained by CP stored in muscles

A

15 second all-out run

139
Q

What is the main fuel of resting skeletal muscles

A

CP

140
Q

What is the main fuel of active skeletal muscles

A

ATP

141
Q

What causes muscle fatigue

A

(1) depletion of metabolic reserves within the muscle fibers (2) damage to the sarcolemma and sarcoplas­mic reticulum (3) a decline in pH within the muscle fibers and the muscle as a whole (4) a sense of weari­ness and a reduction in the desire to continue the activity, due to the effects of low blood pH and sensations of pain

142
Q

What happens to lactic acid during the recovery period

A

During the recovery period, when oxygen is available in abundance, lactate can be converted back to pyruvate

143
Q

List the main characteristics of fast fibers

A
  • Reach peak tension 0.01 sec after stimulation - Large in diameter - Densely packed myofibrils - Large glycogen reserves - Few mitochondria - “White muscles”
144
Q

List the main characteristics of slow fibers

A
  • Take 3x as long to reach peak tension - Half the diameter of fast twitch - Surrounded by a more extensive network of capillaries, for more oxygen - Contain more myoglobin - “Red muscles”
145
Q

What is muscular hypertrophy

A

As a result of repeated, exhaustive stimulation, muscle fibers develop more mitochondria and larger glycogen reserves. Such muscle fibers have more myofibrils than do less­stimulated fibers, and each myofibril contains more thick and thin filaments.

146
Q

What is muscular atrophy

A

A skeletal muscle that is not regularly stimulated by a motor neuron loses muscle tone and mass

147
Q

Why is anaerobic activity only sustainable for only a very short period of time

A

Anaerobic activity is restricted by: 1. The reserves of ATP and CP 2. The amount of glycogen available for glycolysis 3. The tolerance of the muscle to lactic acid

148
Q

List the main structural features of cardiac muscles

A
  • Cardiac muscle cells are relatively small - Typical cardiac cell has a single nucleus - The SR of a cardiac muscle cell lacks terminal cisternae, and its tubules contact the plasma membrane as well as the T tubules
149
Q

List the main functional characteristics of cardiac muscle cells

A
  • Cardiac cells contract without neural stimulation - Nervous system can alter pace of contraction - Contract about 10x as long as skeletal muscle - Sarcolemma structure is different
150
Q

(Chapter 11) What is the main characteristic of parallel muscles? Provide an example.

A

The fascicles (bundles of muscle fibers) are parallel to the long axis of the muscle, e.g., biceps brachii

151
Q

What is the main characteristic of convergent muscles? Provide an example.

A

Muscle fascicles extending over a broad area come together, or converge, on a common attachment site, e.g., pectoralis muscles.

152
Q

What is the main characteristic of a pennate muscle? Provide an example.

A

In a pennate muscle (penna, feather), the fascicles form a common angle with the tendon, e.g., extensor digitorum muscle.

153
Q

Why are pennate muscles able to generate more tension than parallel muscles

A

A pennate muscle has more muscle fibers—and thus more myofibrils—than does a parallel muscle of the same size

154
Q

What is the main characteristic of circular muscles? Provide an example.

A

Aka sphincter. The fascicles are concentrically arranged around an opening, e.g., obicularis oris.

155
Q

What is an antagonist muscle

A

A muscle whose action opposes that of a particular agonist

Advanced A&P (12 decks)

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