Unit 4 Test 2 Pt 1 Flashcards

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1
Q

What are feedback mechanisms?

A

Sensory pathways and responses that your body uses to maintain homeostasis.

Feedback mechanisms are essential for regulating various physiological processes.

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2
Q

What are the two types of feedback mechanisms?

A
  • Negative Feedback
  • Positive Feedback

These mechanisms play crucial roles in homeostatic regulation.

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3
Q

What does negative feedback do?

A

Slows down or stops a response.

Negative feedback is vital for maintaining stability in biological systems.

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4
Q

What does positive feedback do?

A

Amplifies or increases a response.

Positive feedback is often involved in processes that need a definitive outcome, such as childbirth.

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5
Q

What is an example of a stimulus in body temperature regulation?

A

Body temperature exceeds 37°C.

This triggers the feedback mechanism to restore normal temperature.

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6
Q

What type of sensors are involved in body temperature regulation?

A

Sensors like nerve cells with endings in the skin and brain.

These sensors detect changes in temperature and send signals to the control center.

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7
Q

What is the control center for body temperature regulation?

A

Temperature regulatory center in brain.

This center processes information from sensors and coordinates an appropriate response.

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8
Q

What is the effector in the negative feedback loop for body temperature regulation when the body becomes too hot?

A

Sweat glands throughout body.

Sweat glands help cool the body when temperature rises.

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9
Q

Fill in the blank: Negative feedback mechanisms tend to _______ a response.

A

[slow down or stop]

This action is crucial for maintaining homeostasis.

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10
Q

Fill in the blank: Positive feedback mechanisms tend to _______ a response.

A

[amplify or increase]

This is often seen in processes requiring a rapid change.

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11
Q

What is the function of negative feedback in physiological processes?

A

It regulates physiological processes by stopping a cellular response

This mechanism helps maintain homeostasis.

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12
Q

Give an example of negative feedback in the body.

A

Body temperature regulation through shivering and sweating

Shivering increases body temperature, while sweating decreases it.

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13
Q

What happens when body temperature increases in the context of negative feedback?

A

Stopping the response causes the body system to return to its normal state, a ‘set point’

This process helps to re-establish homeostasis.

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14
Q

True or False: Negative feedback mechanisms are responsible for initiating biological processes.

A

False

Positive feedback mechanisms are responsible for initiating and amplifying these processes.

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15
Q

Fill in the blank: Negative feedback mechanisms help to re-establish _______.

A

homeostasis

Homeostasis refers to the body’s ability to maintain a stable internal environment.

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16
Q

How can you describe negative feedback in simple terms?

A

Stopping something that makes homeostasis when it makes homeostasis/ you reach homeostasis
(You stop shivering when your body is warm enough again)

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17
Q

Positive feedback leads to another response but doesn’t lead to _____ while negative feedback does

A

Homeostasis

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18
Q

What is the role of insulin in blood glucose regulation?

A

Insulin stimulates the uptake of glucose by target cells, reducing blood glucose levels

Insulin is secreted by the pancreas in response to increased blood glucose.

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19
Q

What happens when blood glucose levels increase?

A

Stimulates secretion of insulin from the pancreas

This is part of the negative feedback mechanism that helps maintain homeostasis.

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20
Q

How does insulin affect target cells?

A

Causes them to increase uptake of glucose for use or storage

This process reduces the levels of glucose in the blood.

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21
Q

What occurs when insulin decreases blood glucose levels?

A

There is no longer a stimulus to release insulin

This illustrates the negative feedback loop in glucose regulation.

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22
Q

Fill in the blank: An increase in blood glucose typically stimulates secretion of _______.

A

[insulin]

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23
Q

True or False: Insulin increases blood glucose levels.

A

False

Insulin decreases blood glucose levels by facilitating glucose uptake.

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24
Q

What is the role of negative feedback in maintaining homeostasis?

A

Negative feedback helps to maintain homeostasis by counteracting changes in the body.

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25
Q

What stimulates the secretion of glucagon?

A

A decrease in blood glucose.

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26
Q

Where is glucagon secreted from?

A

Pancreatic cells.

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27
Q

What effect does glucagon have on target cells, especially in the liver?

A

It causes the release of glucose through glycogen breakdown.

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28
Q

What happens to blood glucose levels when glucagon acts on the liver?

A

Blood glucose levels increase.

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29
Q

What occurs when blood glucose levels increase?

A

There is no longer a stimulus to release glucagon.

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30
Q

What are insulin and glucagon classified as?

A

Counter-regulatory hormones

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31
Q

What is the primary effect of insulin on blood glucose levels?

A

Lowers glucose levels

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32
Q

What is the primary effect of glucagon on blood glucose levels?

A

Raises glucose levels

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33
Q

Insulin and glucagon have _______ effects on blood glucose levels.

A

Opposite

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34
Q

Which hormone is responsible for increasing blood glucose levels?

A

Glucagon

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35
Q

Which hormone is responsible for decreasing blood glucose levels?

A

Insulin

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36
Q

What is positive feedback?

A

A self-reinforcing process that amplifies responses

Positive feedback loops are mechanisms that enhance or amplify changes; this can lead to exponential growth or decline.

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37
Q

What gas do ripening fruits emit?

A

Ethylene gas

Ethylene is a plant hormone that regulates the ripening process in fruits.

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38
Q

What effect does ethylene gas have on nearby fruits?

A

Stimulates accelerated ripening

This phenomenon is an example of a positive feedback loop in plant biology.

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39
Q

True or False: Positive feedback mechanisms always lead to stability in biological systems.

A

False

Positive feedback can lead to instability and rapid changes in biological systems.

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40
Q

What is cell division in prokaryotes called?

A

Binary fission

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41
Q

What happens during binary fission in prokaryotic cells?

A

The prokaryotic cell elongates as the DNA replicates. A new cell membrane and cell wall are synthesized producing two daughter

This process is a form of asexual reproduction in prokaryotes.

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42
Q

True or False: Binary fission results in the creation of one daughter cell.

A

False

Binary fission produces two daughter cells.

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43
Q

What are the five steps of Binary fission?

A
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44
Q

What are the steps of mitosis?

A
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45
Q

What is the cell cycle simply?

A

Series of events an organisms cells grow and divide to form two genetically identical diploid daughter cells

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46
Q

What are the main phases of mitosis?

A

Interphase and M phase (mitosis) and cytokinesis

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47
Q

What are Quiescent cells?

A

Cells that are not divided but can enter the cell cycle when stimulated - these cells are also known as the G_0 phase (when cells aren’t in the cell cycle)

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48
Q

What is the G_0 phase in the cell cycle?

A

Non-dividing cells that can enter and leave the cell cycle based on environmental signals and cues.

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49
Q

Do all cells divide at the same rate?

A

No, not all cells divide at the same rate.

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50
Q

What determines how often cells divide?

A

How often they are ‘used’ or exposed to damaging conditions.

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51
Q

What is the total time of the cell cycle if it is 24 hours?

A

Interphase: 23/24 hrs and Mitosis (M Phase): 1/24 hrs.

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52
Q

Fill in the blank: Some cells don’t go through the _______.

A

cell cycle.

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53
Q

What do developing organisms require for growth?

A

Production of new cells that each possess a complete genome

This is essential for the organism to grow and develop properly.

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54
Q

What occurs when cell production is greater than cell death?

A

Organismal Growth

This is a key factor in how organisms increase in size and complexity.

55
Q

Why do cells go through the cell cycle in asexually reproducing organisms?

A

To pass their DNA to the next generation

This process ensures genetic material is transmitted during reproduction.

56
Q

How do adult, multicellular organisms utilize the cell cycle?

A

To replace damaged or dying somatic (body) cells

This process is crucial for tissue repair and maintaining healthy body function.

57
Q

What are the three main stages of the cell cycle?

A

Interphase, Mitosis (M Phase), Cytokinesis

58
Q

What are the sub-stages of Interphase?

A

Growth 1, Synthesis of DNA (S phase), Growth 2

59
Q

What is the first stage of Mitosis?

A

Prophase

60
Q

What stage of Mitosis follows Prophase?

A

Metaphase

61
Q

What is the third stage of Mitosis?

A

Anaphase

62
Q

What is the final stage of Mitosis?

A

Telophase

63
Q

What follows Mitosis in the cell cycle?

A

Cytokinesis

64
Q

Fill in the blank: The S phase is responsible for _______.

A

Synthesis of DNA

65
Q

True or False: Cytokinesis is a part of Mitosis.

A

False

66
Q

What is the order of events in the interphase?

A

Growth 1, synthesis of DNA (S phase), growth 2

67
Q

What are the three stages of the cell cycle?

A

Interphase, Mitosis (M Phase), & Cytokinesis

68
Q

What is the purpose of Growth 1 (G1) in the cell cycle?

A

Grow and produce more important molecules and structures

69
Q

What occurs during the DNA Synthesis (S) phase?

A

DNA REPLICATION ONLY

70
Q

What happens during Growth 2 (G2) of the cell cycle?

A

Finish growing and produce more VIP molecules like nucleotides and enzymes and structures (organelles) in preparation for division

71
Q

Fill in the blank: The first step of the cell cycle is _______.

A

Growth 1 (G1)

72
Q

True or False: Cytokinesis is a part of Interphase.

A

False

73
Q

What is the first step of mitosis?

A

Prophase

In prophase, the nucleus dissolves, DNA condenses, and chromosomes become visible. Spindle fibers also begin to form.

74
Q

During which phase of mitosis do chromosomes line up on the equatorial plate?

A

Metaphase

In metaphase, spindle fibers attach to chromosomes, aligning them at the center of the cell.

75
Q

What occurs during telophase?

A

Nucleus reforms and DNA decondenses

The cell membrane also starts to pinch in during telophase.

76
Q

What is the primary action that occurs in anaphase?

A

Contract spindle fibers to move chromosomes to opposite poles

This ensures that each daughter cell will receive an identical set of chromosomes.

77
Q

What is the final step of mitosis called?

A

Telophase

78
Q

Fill in the blank: In prophase, the _______ dissolves.

A

nucleus

79
Q

True or False: In metaphase, chromosomes are not visible.

A

False

Chromosomes are visible and aligned on the equatorial plate during metaphase.

80
Q

What happens to the cell membrane during cytokinesis?

A

It pinches in to form two daughter cells

This process results in the division of the cytoplasm.

81
Q

What is the first step of mitosis?

A

Prophase

In prophase, the nucleus dissolves, DNA condenses, and chromosomes become visible. Spindle fibers also begin to form.

82
Q

During which phase of mitosis do chromosomes line up on the equatorial plate?

A

Metaphase

In metaphase, spindle fibers attach to chromosomes, aligning them at the center of the cell.

83
Q

What occurs during telophase?

A

Nucleus reforms and DNA decondenses

The cell membrane also starts to pinch in during telophase.

84
Q

What is the primary action that occurs in anaphase?

A

Contract spindle fibers to move chromosomes to opposite poles

This ensures that each daughter cell will receive an identical set of chromosomes.

85
Q

What is the final step of mitosis called?

A

Cytokinesis

During cytokinesis, the cytoplasm divides, and the cell membrane pinches in to form two genetically identical daughter cells.

86
Q

Fill in the blank: In prophase, the _______ dissolves.

A

nucleus

87
Q

True or False: In metaphase, chromosomes are not visible.

A

False

Chromosomes are visible and aligned on the equatorial plate during metaphase.

88
Q

What happens to the cell membrane during cytokinesis?

A

It pinches in to form two daughter cells

This process results in the division of the cytoplasm.

89
Q

Here is the mitosis checklist

A
90
Q

Here is the mitosis checklist

A
91
Q

The levels of what type of molecule increase and decrease during the cell cycle?

A

Proteins known as cyclins

92
Q

What do cyclins form complexes with?

A

Cyclin-dependent kinases (CDKs)

Cyclins are essential regulatory proteins that control the cell cycle by interacting with CDKs.

93
Q

What is the primary role of cyclin-dependent kinases (CDKs)?

A

To phosphorylate target proteins that promote cell division

CDKs are activated by cyclins and play a crucial role in regulating the cell cycle.

94
Q

How do cyclins affect CDKs?

A

They activate CDKs

The activation of CDKs by cyclins is essential for the progression of the cell cycle.

95
Q

Fill in the blank: Cyclins and CDKs control the _______.

A

cell cycle

The interaction between cyclins and CDKs is vital for the orderly progression of the cell cycle.

96
Q

True or False: Cyclins phosphorylate target proteins independently.

A

False

Cyclins must first activate CDKs, which then carry out the phosphorylation of target proteins.

97
Q

Here is the interaction between cyclins and cyclin dependent kinases in the cell cycle

A
98
Q

Here is the interaction between cyclins and cyclin dependent kinases in the cell cycle

A
99
Q

What do cyclin-CK complexes control?

A

The cell cycle

Cyclin-CK complexes are critical for regulating the timing and progression of the cell cycle.

100
Q

What activates cyclin-CK complexes?

A

Signals that promote cell division

These signals trigger the activation of cyclin-CDK complexes, allowing the cell cycle to progress.

101
Q

Which phases of the cell cycle are controlled by different cyclin-CDK complexes?

A

G1/S phase, S phase, and M phase

Each cyclin-CDK complex is specific to a particular phase in the cell cycle, ensuring proper progression.

102
Q

True or False: Cyclin-CK complexes are only involved in the M phase of the cell cycle.

A

False

Cyclin-CK complexes are involved in multiple phases, including G1/S and S phases.

103
Q

What is required for cell cycle progression?

A

Successful passage through multiple checkpoints.

104
Q

What does the checkpoint in G1 monitor?

A

Damaged DNA.

105
Q

What does the checkpoint in G2 ensure?

A

That DNA has been fully copied. (This checkpoint is known as the DNA replication checkpoint)

106
Q

What does the spindle assembly checkpoint in the M phase ensure?

A

That the spindles are attached to the chromosomes.

107
Q

Fill in the blank: The DNA damage checkpoint is located in _______.

A

G1 phase.

108
Q

Fill in the blank: The DNA replication checkpoint is located in _______.

A

G2 phase.

109
Q

Fill in the blank: The spindle assembly checkpoint is located in _______.

A

M phase.

110
Q

Image of checkpoints in cell cycle

A
111
Q

How many checkpoints do cells pass through in the cell cycle?

A

3

112
Q

What do cells check for at each checkpoint in the cell cycle?

A

Damage, mutations, and proper internal conditions

113
Q

What happens to healthy cells in the cell cycle?

A

They complete the cell cycle

114
Q

What occurs to damaged or mutated cells during the cell cycle?

A

They enter cell cycle arrest where the cell produces inhibitors of cyclin proteins to prevent progression through the cell cycle

115
Q

What does a cell produce to prevent progression through the cell cycle?

A

Inhibitors of cyclin proteins

116
Q

What is necrosis and when does it occur?

A

Process of cellular death when cells are exposed to extreme conditions

117
Q

What is apoptosis and when does it occur

A

Pre planned cell death in the body as normal cellular multiplication to maintain cellular multiplication

118
Q

What happens when there is a repairable damage or mutation in DNA of a cell?

A

It’s repaired and continues through the cell cycle eventually producing 2 identical daughter cells

119
Q

What happens when there is an irreparable damage or mutation in DNA of a cell?

A

The goes through programmed cell death (apoptosis) and is eliminated and not daughter cells are produced. This prevents diseases

120
Q

What happens when there is an irreparable damage or mutation in DNA of a cell?

A

The goes through programmed cell death (apoptosis) and is eliminated and not daughter cells are produced. This prevents diseases

121
Q

What is the consequence of damage to DNA?

A

It can result in the addition of phosphate groups to p53 proteins from a kinase bringing the cell cycle to a halt in G phase because the P53 with a phosphate enters the DNA Turning a Gene on which pauses the cell cycle to give time for the cell to repair

G phase refers to the gap phase in the cell cycle where the cell prepares for DNA synthesis.

122
Q

What do activated p53 proteins do?

A

They turn on genes that pause the cell cycle.

This action is crucial for preventing the proliferation of damaged cells.

123
Q

Image of p53 in cell cycle

A
124
Q

What type of protein is a p53?

A

Tumor suppressor protein

125
Q

What can disruption of cell cycle checkpoints lead to?

A

Cell death or cancer

126
Q

What type of mutations are common in some cancers?

A

Mutations in p53, rendering it nonfunctional

127
Q

What is a key characteristic of cancer development?

A

Multiple mutations that promote cell division and remove normal checks on cell division

128
Q

What does inactivation of p53 allow a cell to do?

A

Divide in the presence of DNA damage

129
Q

What might a second mutation in a cancer cell do?

A

Accelerate cell division

130
Q

What role does a third mutation play in cancer progression?

A

Interfere with cell cycle checkpoint

131
Q

What is the effect of a fourth mutation in cancer cells?

A

Allow cells to migrate through the body

132
Q

Fill in the blank: Cancer results from multiple mutations that promote _______ and remove the normal checks on cell division.

A

[cell division]

133
Q

Just know this slide

A
134
Q

P53 can trigger ___ or ___

A

Cell cycle arrest or apoptosis