Topic 1 Cell Biology Flashcards

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1
Q

What type of cells do animals, plants and fungi have?

A

Eukaryotic

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2
Q

Where do most of the chemical reactions in a cell happen?

A

In the cytoplasm

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3
Q

What is the function of the cell membrane?

A

It controls the movement of substances in and out the cell

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4
Q

What is the function of the cell wall?

A

It strengthens the cell and supports the plant

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5
Q

What is the function of the permanent vacuole?

A

It is filled with cell sap to help keep the cell turgid

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6
Q

Where is genetic material found in a prokaryotic cell?

A

DNA is a single loopin cytoplasm and also in small rings called plasmids.

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7
Q

Are prokaryotic cells bigger or smaller than eukaryotic cells?

A

Much smaller

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8
Q

What is the size of a micrometre?

A

1/1,000,000th of a metre(1 millionth)

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9
Q

What is the symbol for a micrometre?

A

Looks like an upside down h and an m

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10
Q

What is a micrometre in standard form?

A

1x10(-6)m

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11
Q

What is the size of a nanometre?

A

1/1,000,000,000th of a metre (1 billionth)

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12
Q

What is the symbol for a nanometre?

A

nm

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13
Q

What is a nanometre in standard form?

A

1x10(-9)m

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14
Q

What is the orderof magnitude?

A

number used for size comparisons, for each order of magnitude, number is 10 times previous

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15
Q

What is one order of magnitude?

A

10x greater

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16
Q

What is two orders of magnitude?

A

100x greater

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17
Q

What is three orders of magnitude?

A

1000x greater

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18
Q

Are mitochondria larger or smaller than ribosomes?

A

Larger

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19
Q

What is the cell wall made from?

A

Cellulose

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20
Q

What is the vacuole filled with?

A

Cell sap

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21
Q

What is cell differentiation?

A

When cells become specialised

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22
Q

How are sperm cells adapted for fertilisation?

A
  • head of the sperm contains genetic information
  • tail and streamlined shape to swim to the egg
  • mid piece packed with mitochondria- releases energy for swimming and fertilisation
  • acrosome contains enzymes allow sperm to penetrate/digest way through eggs outer layer
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23
Q

Where is the genetic information contained in a sperm cell?

A

In the nucleus in the head

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24
Q

Where is the mitochondria contained in a sperm cell?

A

The mid piece/middle

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25
Q

Where are the enzymes contained in a sperm cell?

A

In the acrosome (top of the head)

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26
Q

What is the function of the mitochondria in a sperm cell?

A

Release energy needed to swim and fertilise the egg

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27
Q

What is the function of the enzymes in a sperm cell?

A

Allow sperm to penetrate/digest their way through outer layer of the egg

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28
Q

What is the function of the nerve cell?

A

To send electrical impulses around the body

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29
Q

What is the function of the axon in a nerve cell?

A

Carries electrical impulses from one part of the body to another

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30
Q

What is the axon in a nerve cell?

A

Long thin part in the middle

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31
Q

What is the myelin in a nerve cell?

A

A fatty sheath that covers the axon

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32
Q

What is the function of myelin?

A

Insulates nerve cell and increases speed of transmission of nerve impulses

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33
Q

What is the function of synapses in a nerve cell?

A

Junctions (at the end of the axon) that allow impulse to pass from one nerve cell to another

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34
Q

What are dendrites in a nerve cell?

A

Projections from the cell body

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35
Q

What is the function of dendrites?

A

Increase the surface area available to receive information from other nerve cells

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36
Q

What is another name for a nerve cell?

A

Neuron

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37
Q

What are the two ways muscle cells are adapted to contract?

A
  • contain protein fibres
  • contain mitochondria
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38
Q

What is the function of mitochondria in a muscle cell?

A

Provide energy for muscle contraction

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39
Q

What is the function of protein fibres in a muscle cell?

A

Allow muscle cell to contract (get shorter)

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40
Q

What plant cell organelle does a root hair cell not contain?

A

Chloroplasts - root hair cells are underground

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41
Q

What is the function of the root hair cell?

A

To absorb water and mineral ions

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42
Q

How is the root hair cell adapted to increase the rate of absorption?

A

large surface area

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43
Q

Where are xylem found?

A

Plant Stem

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44
Q

What is the function of the xylem?

A

Transport water and mineral ions from roots to leaves

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45
Q

How are xylem cells adapted to provide support to the plant?

A

Thick cell walls containing lignin

46
Q

How is the xylem adapted to easily transport water and minerals?

A

Xylem cells have no end walls and no cytoplasm so they form a continuous hollow tube allowing substances to flow freely

47
Q

What is the function of the phloem?

A

Transports products of photosynthesis up and down the plant

48
Q

Why do the sieve tubes in the phloem have companion cells?

A

Sieve tubes have limited cytoplasm so contain little mitochondria - companion cells contain mitochondria

49
Q

What is the function of the companion cells in the phloem?

A

Contain mitochondria to provide energy for transport of substances

50
Q

What are the advantages of electron microscopes?

A
  • higher magnification
  • higher resolution
51
Q

How do bacteria multiply?

A

By simple cell division- binary fission

52
Q

What is the formula to calculate the number of bacteria in a population after a certain time if given the mean division time?

A

Number of bacteria = 2(to the power of n when n equals number of rounds of division)

53
Q

What are the 2 ways to culture bacteria?

A
  • in a nutrient broth solution
  • as colonies on an agar gel plate
54
Q

How many chromosomes does a human body cell have?

A

23 pairs or 46 in total

55
Q

How many chromosomes do gametes have?

A

23 (not paired)

56
Q

What are the stages of cell division called?

A

The cell cycle

57
Q

What is the first stage of the cell cycle?

A
  • DNA replicates to form two copies of each chromosome
  • cell grows and copies it’s internal structures eg mitochondria, ribosomes
58
Q

What is the second stage of the cell cycle?

A
  • (mitosis) one set of chromosomes is pulled to each end of cell and nucleus divides
59
Q

What stage of the cell cycle is mitosis?

A

Second stage

60
Q

What is the third stage of the cell cycle?

A

Cytoplasm and cell membranes divide to form two identical cells

61
Q

What types of cells can stem cells in bone marrow differentiate into?

A

Blood cells

62
Q

When are bone marrow transplants used?

A
  • to treat blood cancers eg leukaemia
63
Q

What are stem cells?

A

Undifferentiated cells, can divide to produce more undifferentiated cells/different types of cells

64
Q

What are the 3 types of stem cells?

A

Embryonic
Adult
Meristem

65
Q

What can stem cells from embryos and bone marrow be used for?

A

Cloned and made to differentiate into specialised cells for medicine/research

66
Q

Where are adult stem cells found?

A

Only in certain places, bone marrow

67
Q

What can adult stem cells do?

A

Form certain types of cell, blood cells

68
Q

What can stem cells from bone marrow be used for in medicine?

A

Replace faulty blood cells

69
Q

What are 2 medical conditions that can be treated using stem cells?

A

Diabetes
Paralysis

70
Q

How can embryonic stem cells be used to treat diabetes?

A

Make insulin-producing cells

71
Q

How can embryonic stem cells be used to treat paralysis?

A

Make nerve cells

72
Q

What is therapeutic cloning?

A

Embryo produced with same genes as patient

73
Q

Why is therapeutic cloning useful for medical treatment?

A

Stem cells from embryo have same genes so not rejected by patients body

74
Q

What is a risk of using stem cells in medicine?

A

Stem cells grown in lab may become contaminated with virus, transfer to patient

75
Q

Why are some people against stem cell research?

A

Human embryos are a potential human life

76
Q

What is an argument for stem cell research?

A

Embryos usually unwanted ones from fertility clinics, would be destroyed if not used for research

77
Q

Where are stem cells found in plants?

A

Meristems

78
Q

What can cells in meristem tissues do throughout the plants life?

A

Differentiate into any type of plant cell

79
Q

What can stem cells from meristems be used for?

A

Produce clones of whole plants quickly and cheaply

80
Q

What are 2 things, cloning stem cells from meristems, can be used to do?

A

Rare species cloned to prevent extinction
Grow crops of identical plants with desired features for farmers (disease resistance)

81
Q

What is diffusion?

A

Spreading out of particles from area of higher concentration to an area of lower concentration

82
Q

What 2 substances does diffusion happen in?

A

Solutions and gases

83
Q

Which 3 factors affect the rate of diffusion?

A

Concentration gradient (difference in concentration)
Temperature
Surface area of membrane

84
Q

How does a bigger concentration gradient (difference in concentration) affect the diffusion rate?

A

Faster

85
Q

How does a higher temperature affect the diffusion rate?

A

Faster- particles have more energy

86
Q

What can only pass through cell membranes?

A

Small molecules

87
Q

What is osmosis?

A

Movement of water from dilute solution to concentrated solution across partially permeable membrane

88
Q

What type of movement is diffusion?

A

Random and net (overall) movement

89
Q

What is a partially permeable membrane?

A

Very small holes in it

90
Q

What is active transport?

A

Substances move from dilute solution to more concentrated solution against concentration gradient

91
Q

What does active transport require?

A

Energy from respiration

92
Q

When is active transport used in the gut?

A

If Lower concentration of sugar molecules in gut but higher concentration of sugar molecules in blood

93
Q

What does active transport allow between blood and the gut?

A

Glucose taken into bloodstream and transported to cells for respiration

94
Q

How does the waste product urea diffuse?

A

From cells into blood plasma for excretion by kidneys

95
Q

What are the 4 things the effectiveness of an exchange surface are increased by?

A

Large surface area
Thin membrane - short diffusion distance
Efficient blood supply (in animals)
Ventilated gas exchange surfaces (in animals)

96
Q

Why can gases/dissolved substances diffuse directly into a single-celled organism?

A

Large surface area to volume ratio

97
Q

If an organism is larger, how is its surface area to volume ratio affected?

A

Smaller

98
Q

What does the ease of an organism to exchange substances with the environment depend on?

A

Surface area to volume ratio

99
Q

Why do multicellular organisms need exchange surfaces?

A

Smaller surface area compared to volume- not enough substances can diffuse from outer surface to supply entire volume

100
Q

What is the inside of the small intestine covered in?

A

Villi

101
Q

What do villi have to assist quick absorption of digested food into the blood?

A

Network of capillaries (good blood supply)
Single layer of surface cells

102
Q

What is a gas exchange surface in fish?

A

Gills

103
Q

What is diffused in the gills?

A

Oxygen diffuses from water into blood, CO2 diffuses from blood into water

104
Q

What is each gill made up of?

A

Lots of thin plates called gill filaments

105
Q

how are gil filaments adapted for gas exchange?

A

large surface area, increased by lamellae

106
Q

what are gil filaments covered in?

A

lots of tiny structures called lamellae

107
Q

what are gil filaments covered in?

A

lots of tiny structures called lamellae

108
Q

In what 2 ways are the lamellae adapted to speed up diffusion?

A

lots of blood capillaries
thin surface layer of cells - minimise diffusion distance

109
Q

how is a large concentration gradient maintained between water and blood in the Gills?

A

blood flows through lamellae in one direction, water flows in opposite direction

110
Q

how is a large concentration gradient maintained between water and blood in the Gills?

A

blood flows through lamellae in one direction, water flows in opposite direction