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biology > cell biology (T1) > Flashcards

cell biology (T1) Flashcards

1
Q

what are eukaryotic cells? give examples.

A

a more complex cell that has a nucleus. e.g. animal and plant cell

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2
Q

what are prokaryotic cells? give examples.

A

a simple cell without a nucleus. e.g. bacteria

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3
Q

where is the genetic material in eukaryotic and prokaryotic cells?

A

in eukaryotes it is enclosed in the nucleus, in prokaryotes it is a small loop of DNA and in plasmids.

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4
Q

what is the prokaryotic cell wall composed of?

A

Peptidoglycan

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5
Q

what are plasmids

A

small circular loops of dna found free in the cytoplasm and seperate from main dna. they carry genes that provide genetic advantages e.g. antibiotic resistance.

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6
Q

what is order of magnitude?

A

a power to the base of 10 used to quantify and compare size e.g. 10^2 is 1 order of magnitude bigger than 10^1.

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7
Q

what is a cm, mm, µm, nm

A

1 x 10 ^-2m, 1 x 10^-3 m, 1 x 10^-6, 1 x 10^-9

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8
Q

list the components of both plant and animal cells

A

cell membrane, mitochondria, cytoplasm, ribosomes, nucleus

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9
Q

list the additional components found in plant cells

A

permanent vacuole, chloroplast, cell wall

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10
Q

other than storing genetic information, what is the function of the nucleus

A

controls cellular activities

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11
Q

describe the structure of cytoplasm

A
  • fluid component of cell
  • contains organelles, enzymes and dissolved ions and nutrients
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12
Q

what is the function of cytoplasm

A

site of cellular reactions

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13
Q

what is the function of the cell membrane

A

controls what goes in and out of the cell

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14
Q

what is the function of mitochondria

A

site of aerobic respiration

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15
Q

what is the function of the ribosome

A

site of protein synthesis

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16
Q

what is the plant cell wall made of

A

cellulose

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17
Q

what is the function of the plant cell wall

A

provides strength

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18
Q

what does the permanent vacuole contain

A

cell sap

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19
Q

what is the function of the permanent vacuole

A

supports the cell

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20
Q

what is the function of chloroplasts

A

site of photosynthesis

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21
Q

describe how sperm cells in animals are adapted to their function

A
  • (haploid) nucleus contains genetic information of father
  • tail enables movement
  • mitochondria provides energy for the cell
  • acrosome contains enzymes that digest the egg cell membrane
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22
Q

describe how nerve cells are adapted to their function

A
  • long axon allows electrical impulses to be transmitted all over the body
  • dendrites from the cell body connect to and receive impulses from other nerve cells, muscles and glands
  • myelin sheath insulates the axon and speeds up the transmission of impulses along the nerve cell
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23
Q

describe how muscle cells are adapted to their function

A
  • arrangement of protein filaments allow them to slide over each other to produce muscle contraction
  • mitochondria to provide energy for muscle contraction
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24
Q

describe how root hair cells are adapted to their function

A
  • large surface area to absorb nutrients and water from surrounding soil
  • thin walls that do not restrict water absorption
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25
Q

describe how xylem cells are adapted to their function

A
  • no end walls to provide a continuous route for water to flow
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26
Q

describe how phloem cells are adapted to their functions

A
  • sieve plates let dissolved amino acids and sugar to be transported up and down the stem
  • companion cells provide energy needed for active transport of substances along the phloem
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27
Q

what is cell differentiation

A

the process by which cells become specialised

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28
Q

why is differentiation important

A

allows production of different tissues and organs that perform various vital functions in the human body

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29
Q

at what point in their life cycle to most animal cells differentiate

A

early in their life cycle

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30
Q

for how long do plant cells retain their ability to differentiate

A

throughout their life

31
Q

what is the purpose of cell division in mature animals

A

repair and replacement of cells

32
Q

what changes does a cell go through as it differentiates

A

becomes specialised by developing different sub-cellular structures to enable it to perform a specific function

33
Q

define magnification

A

the number of times bigger an image appears compared to the actual size of the real object

34
Q

define resolution

A

the smallest distance between two objects that can still be distinguished

35
Q

how does a light microscope work

A

passes a beam of light through a specimen which travels through the eyepiece lens allowing the specimen to be observed

36
Q

what are advantages of light microscopes (4)

A
  • inexpensive
  • easy to use
  • portable
    -can observe both live and dead specimens
37
Q

what are disadvantages of light microscopes

A
  • limited resolution
  • lower magnification than electron microscopes
38
Q

how does an electron microscope work

A

uses electron beams which are focused by magnets the electrons hit a fluorescent screen which emit visible light producing an image

39
Q

what are advantages of electron microscopes

A
  • greater magnification
  • greater resolution
40
Q

why do electron microscopes have a higher magnification and resolution

A

they use a beam of electrons with a shorter wavelength than light

41
Q

what are disadvantages of electron microscopes

A
  • expensive
  • hard to use
  • not portable
    -can only see dead specimens
42
Q

magnification equation

A

magnification= image size ÷ real size

43
Q

how many chromosome are found in human body cells

A

46

44
Q

how many chromosomes are found in gametes

A

23

45
Q

how are chromosomes arranged in the nucleus of a human body cells

A

46 chromosomes form 23 pairs

46
Q

what are the three main stages of the cell cycle

A
  • chromosomes duplicate
  • mitosis
    -cell divides
47
Q

why is mitosis important

A
  • produces identical cells that all have the same genetic information
  • produces additional cells for growth and repair
48
Q

describe the first stage of the cell cycle

A

cells grow, replicate dna and synthesise more organelles

49
Q

describe the second stage of the cell cycle

A

each chromosome in a pair is pulled to opposite poles of the cell then the nucleus divides

50
Q

describe the third stage of the cell cycle

A

the cytoplasm and cell membrane split, two daughter cells are provided

51
Q

what is a stem cell

A

unspecialised cell capable of differentiating into other cell types

52
Q

what is the function of stem cells in embryos

A

embryonic stem cells can differentiate into any type of cell and they can be used to treat conditions such as paralysis and diabetes

53
Q

what is the function of the stem cells in bone marrow

A

adult stem cells can differentiate into several cell types to replace dead or damaged tissues, bone marrow turns into many types of blood cell

54
Q

what is the function of stem cells in plant meristems

A

to differentiate into any type of cell required by the plant

55
Q

what is therapeutic cloning

A

cloning method where an embryo is produced with the same genetic makeup as the patient. the stem cells which originate from the embryo will not be rejected by the patients immune system so can be used to treat certain medical conditions

56
Q

what are advantages of cloning plants using meristem stem cells

A
  • can prevent rare plants from becoming extinct
  • can produce large number of plants with a favourable characteristic
  • can produce identical plants for research
57
Q

what are issues associated with the use of stem cells

A
  • many embryonic stem cells are sourced from aborted embryos -> some people have an ethical/ religious objection
  • development of stem cell therapies is slow, difficult and expensive.
  • adult stem cells with viruses could transfer infections to the patient
  • if donor cells do not have a similar genetic makeup to the patient, an immune response could be triggered
58
Q

what is diffusion

A

the net movement of particles from an area of high concentration to an area of low concentration

59
Q

what three main factors affect the rate of diffusion

A
  • surface area
  • concentration gradient
  • temperature
60
Q

give examples of substances transported by diffusion in the lungs and kidney

A
  • lungs: oxygen diffuses into the blood from the lungs and carbon dioxide diffuses into the lungs from the blood
  • kidney: urea diffuses from the cells into blood plasma so it can be excreted in urine
61
Q

how are single-celled organisms adapted for diffusion

A

large surface area:volume ratio - maximises the rate of diffusion

62
Q

what four factors increase the effectiveness of a gas exchange surface

A
  • good blood supply
  • large surface area
  • thin walls
  • ventilation
63
Q

what is osmosis

A

the movement of water molecules from an area with a high concentration of water to an area of low water concentration through a partially permeable membrane

64
Q

what is meant when a solution is isotonic to a cell

A

the water concentration of the solution and the cell is the same

65
Q

what is meant when a solution is hypertonic to a cell

A

the water concentration of the solution is lower (higher solute concentration) than the cell

66
Q

what is meant when a solution is hypotonic to a cell

A

the water concentration of the solution is higher (lower solute concentration)

67
Q

what will happen to an animal cell in a very hypotonic solution

A

water will move into the cell until it bursts

68
Q

what will happen to an animal cell in a very hypertonic solution

A

water will leave the cell causing it to shrivel up

69
Q

how do plant leaves and stems remain rigid

A

water moves in by osmosis causing the vacuole to swell and the cytoplasm to press against the cell wall

70
Q

what may happen when a plant cell is places in a very hypertonic solution

A

water moves out of the cell by osmosis causing the vacuole and cytoplasm to decrease in size. the cell membrane may pull away from the cell wall.

71
Q

what is active transport

A

the movement of molecules from an area of low concentration to an area of high concentration against the concentration gradient, using energy from respiration

72
Q

how do root hair cells use active transport

A

take up mineral ions from a lower concentration in soil, ions such as magnesium and nitrate are needed for healthy growth

73
Q

how is active transport used to absorb the products of digestion

A

active transport is used to transport glucose from a low concentration to a higher concentration in the blood - glucose is then transported into tissues to be used in respiration.

biology (7 decks)

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