Bio Sem 1 Rev Flashcards

93%

1
Q

Why is homeostasis important

A

To maintain a balanced level of temp/blood sugar level or the cells of the body to function

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2
Q

Define Homeostasis

A

The maintenance of a stable internal environment within the body despite changes in the external environment

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3
Q

Factors under homeostatic control

A

Temp - 36.5-37.5 C
pH - 7.35-7.45
Blood sugar levels
O2 CO2 concentration
Fluid balance

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4
Q

Stimulus

A

Change in the internal or external environment

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5
Q

Receptor

A

Structures that detect changes to the environment (usually cells)

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6
Q

Control Centre / Modulator

A

Cells / Organs (often the nervous system) that “decide” on a response

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7
Q

Effector

A

The molecule, cell or organ that produces a response

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8
Q

Response

A

Any change in the cell, organ or organism caused by the stimulus

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9
Q

Stimulus - Response Model (in order)

A

Stimulus –> Receptor –> Modulator –> Effector –> Response

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10
Q

Types of Receptors

A

Thermoreceptors
Nociceptors
Baroreceptors
Chemoreceptors
Photoreceptors

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11
Q

Define Thermoreceptors

A

Detects changes in Temperature

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12
Q

Define Nociceptors

A

Detects painful stimuli (skin)

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13
Q

Define Baroreceptors

A

Detects changes in pressure

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14
Q

Chemoreceptors

A

Detects changes in chemical concentration

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15
Q

Photoreceptors

A

Detects changes in light

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16
Q

Negative Feedback

A

The response acts to counteract the internal stimulus to return the body to the set point (homeostasis)

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17
Q

Positive Feedback

A

The response acts to increase the initial stimulus. (pushes the body away from a set point)

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18
Q

Hypothalamus

A

Structure deep in the brain responsible for monitoring and controlling your body temp

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19
Q

Thermoregulation - Two ways the body cools itself down

A

Sweating

Vasodilation

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20
Q

Vasodilation

A

Capillaries under the skin widen when you get hot, allowing more blood to circulate closer to the surface of the body

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21
Q

Thermoregulation - 3 things the body does to keep warm

A

Vasoconstriction

Piloerection

Shivering

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22
Q

Vasoconstriction

A

Capillaries under the skin shrink when you get cold, keeping the blood away from the surface of the body

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23
Q

Piloerection (Goosebumps)

A

Small muscles at the base of the hair follicles pull the hair so it stands up (traps heat)

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24
Q

How does SA:V affect heat loss and insulation?

A

Greater SA:V allows for easier heat loss

Lesser SA:V allows for insulation

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25
Q

Hypoglycemia

A

Low blood sugar level

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26
Q

Hyperglycemia

A

High blood sugar level

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27
Q

2 hormones from the pancreas that regulate blood glucose levels

A

Insulin

Glucagon

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28
Q

Glucose

A

Sugar molecule necessary for cellular resp and functioning of all cells

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29
Q

Glycogen

A

Stored form of glucose (cannot be used by cells)

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30
Q

Glucagon

A

A hormone that helps to raise glucose concentration in the blood

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31
Q

When is Glucagon released? And where is it released from?

A

Where: secreted from alpha cells

When: Secreted when blood sugar levels are low

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32
Q

How does glucagon help increase blood glucose levels?

A

Stimulates the liver to convert glycogen into glucose and release it into the blood

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33
Q

Insulin

A

Lowers blood glucose levels

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34
Q

When is insulin released and where is it released from?

A

Where: secreted from beta cells

When: secreted when blood sugar levels are high

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35
Q

How does insulin help lower blood glucose levels?

A

Stimulates liver to convert glucose from the blood into glycogen

Can target skeletal muscles and cells to take up more glucose

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36
Q

Islets of Langerhan

A

Pancreatic cell that produces hormones (Insulin and glucagon)

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37
Q

Type 1 diabetes

A

The immune system destroys the insulin-making cells in the pancreas

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38
Q

Type 2 diabetes

A

Body cells become resistant (no longer respond) to insulin

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39
Q

Phospholipid Structure

A

Hydrophilic head
Hydrophobic tails

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40
Q

Phospholipid Bilayer Structure

A

Heads point out tails hide in middle of the layer

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41
Q

Main components of the plasma membrane

A
  • Phospholipids
  • Cholesterol
  • Proteins
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42
Q

Cholesterol

A

Scattered through phospholipid tails

Helps control the fluidity of the membrane

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43
Q

Transport proteins

A

Channel and carrier proteins assist the movement of substance through the cell membrane

44
Q

Types of transport

A

Passive transport

Active transport

45
Q

Types of passive transport

A

Osmosis (fluids)

Diffusion (high to low concentration gradient)

Facilitated Transport - Assisted (no energy

46
Q

Types of active transport

A

Vesicles

Protein pumps

47
Q

Active transport - protein pumps

A

Movement of molecules across the membrane, against the concentration gradient , requires energy, only occurs through carrier proteins

48
Q

ATP - name

A

Adenosine triphosphate

49
Q

Draw and Label the ADP -ATP cycle

A

srryz no image

50
Q

Bulk transport

A

Movement of molecules in and out of cell via vesicles (requires energy)

51
Q

Vesicles

A

Small bubbles of phospholipids

52
Q

MRSGREEN

A

Movement
Respiration
Sensitivity
Growth
Reproduction
Equilibrium
Excretion
Nutrition

53
Q

Cell Theory

A
  • All organisms are made of cells
  • The cell is the most basic unit of life
  • All existing cells are produced by other living cells
54
Q

Types of cells

A

Prokaryotic

Eukaryotic

55
Q

Prokaryotic

A

Cells without a nucleus or other membrane-bound organelles

56
Q

Eukaryotic

A

Cells with a nucleus and membrane bound organelles

57
Q

Cytoplasm/Cytosol

A
  • Fluid-like substance inside the cell
  • All cell organelles sit within the fluid and important chemical reactions take place here
58
Q

Ribosome

A
  • Non-membrane bound organelle
  • Site of protein synthesis
  • Found floating in cytoplasm or attached to Endoplasmic Reticulum
59
Q

Cytoskeleton

A

Structure that helps cells maintain shape and internal organisation

60
Q

Organelles only in Plant cells

A

Cell wall

Chloroplast

61
Q

Nucleus

A
  • the control centre of the cell
  • contains the main gene material
  • Surrounded by a membrane
62
Q

Nucleolus

A
  • a small dark region within the nucleus
  • responsible for making ribosomes
63
Q

Endoplasmic Reticulum

A
  • Transport system in the cell
  • Made of connected network of membranes and is found close to the nucleus
64
Q

Golgi Body

A

Prepares and packages cellular products for export out of the cell

65
Q

Vacuole

A
  • Membrane-bound structure
  • Stores important cellular materials (water, waste, sugars)
  • plant cells have a large central vacuole
66
Q

Lysosome

A
  • Stomach of the cell
  • contains digestive enzymes
  • breaks down complex molecules
67
Q

Mitochondria

A
  • Site of cellular respiration
  • Generates ATP
68
Q

Centriole / Centrosome

A
  • Structure that appears in animal cells when dividing
  • Helps separate the chromosomes
69
Q

Chloroplasts

A

Green in colour- double membrane containing green pigment chlorophyll which carries on photosynthesis

70
Q

Photosynthesis chemical formula

A

6CO2 + 12H2O – light and chlorophyll–> C6H12O6 + 6O2 + 6H2O

71
Q

Phases of photosynthesis

A

Phase One

Light-dependent phase (LDP): This occurs in the thylakoid/grana, the light energy is captured by the chlorophyll, which is used to split water molecules. The water molecules then release 2H+ and oxygen as well as energy. These products are used as waste and cell functions.

Waste = oxygen for us.

For the organelle = energy is used to charge ADP and energy with H+ is used NADP+ to NADPH.

Carrier molecules: ATP and NADPH get charged up by the light dependent reactions. ATP carry energy, NADPH carry H to the light independent reactions.

Phase Two:

Light-independent phase (LIP): Occurs in the stroma and doesn’t require the help of light. Only needs carbon dioxide from the atmosphere and the products of LDP. The products supply the energy and H to produce glucose from CO2. Then after the reaction is done, the used products (ATP and NADPH) turn into ADP and NADP+ to then cycle back to the LDP (Light dependent phase). Happens in Calvin Cycle.

72
Q

Light Dependent Phase - Location, Inputs, Outputs

A

Location - Grana / Thylakoid

inputs - Light, Water, NADP+ and ADP

Outputs - Oxygen, NADPH and ATP

73
Q

Light Independent Phase - Location, Inputs, Outputs

A

Location - Stroma

Inputs - Carbon dioxide, NADPH and ATP

Outputs - Glucose, NADP+ and ADP

74
Q

Mutagen

A

changes in cell that causes Mutations

75
Q

SA:V ratio and how it affects cells

A

Greater SA:V ratio means the cells export and import resources faster

Lesser SA:V ratio means the cells export and import resources slower

76
Q

Difference between Autotroph and Heterotroph

A

Autotroph produces its own food

Heterotrophs cannot produce its own food and rely on other sources of food (autotrophs or other heterotrophs)

77
Q

Equation for Aerobic cellular respiration

A

C6H12O6 + 6O2 → 6CO2 + 6H2O

78
Q

When does aerobic cellular respiration take place?

A

When oxygen is present

79
Q

3 main stages of cellular respiration

A

Glycolysis

Kreb Cycle

Electron Transport Cycle

80
Q

Glycolysis - Location, inputs, outputs

A
  • Occurs in cytoplasm
  • Input: glucose, ADP, NAD+
  • Output: Pyruvate 2 ATP and NADH
81
Q

Kreb Cycle

A
  • occurs in mitochondrial matrix
  • Input: pyruvate (acetyl COA), ADP, NAD+, FAD+
  • Output: CO2, NADH, FADH2, 2 ATP
82
Q

Electron Transport Cycle

A
  • Occurs in the inner membrane
  • input: NADH, FADH2, O2
  • Output: H2O, 26 or 28 ATP, NAD+, FAD+
83
Q

Anaerobic: No oxygen

A
  • Makes 2 ATP + water
  • Lactic acid or alcohol
84
Q

Compare products of aerobic respiration with products of anaerobic respiration

A

Photosynthesis converts carbon dioxide and water into oxygen and glucose. Glucose is used as food by the plant and oxygen is a by-product. Cellular respiration converts oxygen and glucose into water and carbon dioxide. Water and carbon dioxide are by- products and ATP is energy that is transformed from the process.

85
Q

Describe binary fission in prokaryotes

A

1 cell dividing into 2 identical daughter cells

86
Q

Purpose of cell replication

A
  • allows the body to renew itself
  • repair damages
87
Q

4 phases of the eukaryotic cell cycle

A

G1
S
G2
M-phase (Mitosis

88
Q

G1

A

cell growth new copies of organelles are made

89
Q

S

A

DNA replication

90
Q

G2

A

growth and preparation for division

91
Q

Prophase

A
  • Chromatin condenses to chromosomes
  • Nuclear membrane/envelope starts to break down.
  • Spindle fibres form
92
Q

Late Prophase

A
  • Chromosomes attach to spindle fibres (via centromere)
  • Nuclear membrane completes breakdown
  • Centrosome is position at poles
93
Q

Metaphase

A

Chromosomes line up single file down the centre of the cell

94
Q

Anaphase

A

Spindle fibres contract pulling apart the double stranded chromosomes (sister chromatids)

95
Q

Telophase

A

Nuclear membrane reforms. Chromosome recondense

96
Q

Cytokinesis

A

Cytoplasm splits forming 2 daughter cells (part of M-phase but not mitosis)

Animal cells it forms a cleavage furrow

Plant cells it forms a cell plate

97
Q

Chromatin

A

A mixture of DNA and proteins that form the chromosomes

98
Q

Chromosome

A

X shaped thingy that carries curled up DNA

99
Q

Centromere

A

Middle of the Chromosome

100
Q

Chromatids

A

Half of the chromosome

101
Q

DNA levels between G1 to G2

A

DNA doubles

102
Q

Apoptosis

A
  • Controlled cellular death
  • Prevents cancer
103
Q

Name 3 cell checkpoints and explain what it’s for

A

G1 - verifies that the cell has grown to the correct size, has synthesised enough protein for DNA replication, and checks if the DNA has been damaged during mitosis and cell growth.

G2 - ensures that DNA has replicated properly in the S phase, and that the cell has enough resources for mitosis.

Metaphase - checks the formation of the spindle fibres. If the chromosomes are lined up in the correct location, the cell proceeds to anaphase.

104
Q

Difference between tumor suppressor genes and proto-oncogenes

A

Proto-oncogenes - make cells divide when they need to

Tumor suppressor genes - They make sure everything in the cell is as it should be

105
Q

Mutation in proto - oncogenes causes …

A

Uncontrollable cell growth

106
Q

Mutation in tumor suppressor genes

A

doesn’t stop cell growth