CELL BIOLOGY Flashcards

CELL BIOLOGY

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1
Q

what is a cell?

A

smallest unit that lives on its own and makes up all living organisms and the tissues of the body

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2
Q

type of organisms: prokrayotic

A

prokaryote - small and simple e.g bacteria

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3
Q

type of organism: eukaryotic

A

eukaryote - large and complex e.g animal, plant cells

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4
Q

Plant and animal cells both have …..

A

cell membrane: controls what goes in and out, holds cell together
cytoplasm: chemical reactions (gel like substance)
nucleus:genetic material->controls cell activity
mitrochondia:aerobic respiration-> glucose and o2 to energy
ribosome:protein synethsis

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5
Q

what are the features of an animal cell?

A

cell membrane
nucleus
ribosomes
mitochondria
cytoplasm

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6
Q

what are the features of a plant cell? (extra things)

A

rigid cell wall:strengthens/supports cell, made of cellulose
permanant vacuole:cell sap
chloroplast:photosynthesis -> food, contains chlorophyll (absorb light)

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7
Q

what are the features of a bacteria cell?

A

cell membrane
cell wall
cytoplasm
plasmids:small rings of DNA
ribosomes
flagella

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8
Q

magnification =

A

image size/real size

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9
Q

what is the difference between electron and light microscopes?

A

electron- uses electrons
- higher magnification and
resolution
- small things in detail like
ribosomes
light- uses light
- can see individual cells

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10
Q

microscope PRACTICAL - making the slide

A
  1. add a drop of water to a slide
  2. cut an onion and separate the epidermal tissues using tweezers
  3. put it on the slide on the water
  4. add a drop of iodine on it
  5. add a cover slip on top - try to not get any air bubbles
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11
Q

microscopy PRACTICAL

A
  1. clip the slide onto the stage
  2. select the lowest objective lens
  3. use the coarse adjustment knob to move the stage up
  4. look through the eyepiece
  5. move the stage up/down until its focused
  6. keep changing the magnification
  7. draw your observation
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12
Q

what is cell differentiation?

A

the process where a cell changes to become speciallised for its function

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13
Q

what are examples of speciallised cells?

A

sperm
nerve
muscle
root hair
pholem/xylem

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14
Q

what is the function of sperm cells? and how?

A

reproduction- male to female DNA
long tail, streamlined head - help swim to egg
mitochondria - energy
enzymes in head - digest through egg cell membrane

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15
Q

what is the function of nerve cells? and how?

A

rapid signalling - carry electrical signals
long - cover more distance
branched connections - connect and form network of nerve cells

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16
Q

what is the function of muscle cells? and how?

A

contraction
long - more space to contract
mitrochondria - energy

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17
Q

what is the function of root hair cells? and how?

A

absorb water and minerals on surface of plant roots
hairs in soil - stick into soil
big SA - faster absorbtion

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18
Q

what is the function of phloem/xylem cells? and how?

A

transport food and water in plants
long (joined end to end)
xylem - hollow
phloem - not many subcellular structures so things can flow easily in/out

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19
Q

what are stem cells?

A

undifferentiated cells that can differentiate to other cells and be cloned

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20
Q

where are stem cells found?

A

human embryo
bone marrow - adults only

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21
Q

what can adult stem cells become?

A

only certain cells like red blood cells

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22
Q

how can stem cells cure disease?

A

healthy stem cells can be transferred to replace faulty cells

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23
Q

give an example of a stem cell curing disease

A

embryonic can be made to an insulin-producing cell for people with diabetes OR to nerve cells for paralyzed people

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24
Q

what is embryonic cloning?how does it work?

A

when an embryo is made to have the same genetic info so the patients body doesnt reject the stem cell

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25
Q

why is medicinal use for stem cells dangerous?

A

ones grown in labs can become contaminated with a virus which can be passed on

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26
Q

why are people against the use of stem cells?

A

human embryos shouldnt be used for experiments since each of them are potential human life

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27
Q

where is stem cells found in plants?

A

meristems

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28
Q

how are stem cells in plants used?

A

produce clones - fast and cheap
differentiate into any cell
prevent rare plant species from being wipes out
grow plants with desirable features

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29
Q

what is a chromosome

A

coils of DNA (in nucleus)

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30
Q

how many pairs of chromosomes in the human body?

A

23 pairs

31
Q

what does a chromosome do?

A

different genes control the development of characteristics like hair and eye colour

32
Q

when can animal and plant cells differentiate?

A

animal cell differentiate at an early stage
plant cells retain the ability to differentiate throughout life.

33
Q

before cell division, the cell has to?

A

increase amount of mitochondira and ribosomes. it then can be duplicated so theres a copy for each new cell, creating x shaped chromosomes

34
Q

after the increase of mitochondria and ribosomes, what do cells do

A

iduplicated so theres a copy for each new cell, then forming x shaped chromosomes - each arm of it is a copy of the other

35
Q

how does mitosis take place?

A
  1. chromosomes line up in the middle
  2. cell fibres pull them apart and go to opposite ends
  3. membranes form around each set of chromosome which become the nuclei of 2 new cells
  4. the nucleus has divided
  5. cytoplasm and membrane divide
  6. 2 daughter cells - same DNA as parent cells
36
Q

what is diffusion?

A

gradual particle movement from an area of high conc to low

37
Q

what does diffusion happen in?

A

in gases and solutions - particles can move freely and randomly

38
Q

what affects diffusion rate?why?

A

the larger the conc gradient/temp/SA, the faster diffusion rate - more energy to move

39
Q

what moves by diffusion?

A

ONLY dissolved substances can diffuse through the cell membrane e.g oxygen, glucose, water, amino acids

40
Q

what is osmosis? (type of diffusion)

A

movement of water molecules across a semi permeble membrane from an area of high water conc to lower

41
Q

what is a semi permeble membrane?

A

membrane with small holes in it so bigger molecules like starch and sucrose cant pass

42
Q

what happens to the water molecules during osmosis?

A

they randomly move around
there are more water molecules to one side so theres a steady net flow into the area with stronger sugar solution, which eventually becomes more dilute

43
Q

osmosis PRACTICAL

A
  1. cut a potato into equal cylinders with no skin
  2. get beakers and put different sugar solutions in each one e.g. 0.2mol/dm3, 0.4, 0.6, 0.8, 1
  3. another beaker should be pure water
  4. weigh mass of the cylinders
  5. place them in the beakers
  6. leave for 20 minutes
  7. take out and dry
  8. measure their masses again
  9. if increase in mass - osmosis has take in water
    if decrease - water has been taken out
44
Q

what are the variables in the osmosis practical?

A

independant - conc of sugar solution
dependant - potato mass
control - vol of solution, temp, time, type of sugar, potato thickness

45
Q

what is active transport?

A

movement of dissolved molecules into/out of a cell from a lower concentration to a higher concentration

46
Q

what do root hair cells take in? how do they do this?

A

minerals and water - each branch has million of microscopic roots that gives the plant a larger SA for absorption from the soil which is needed for a healthy growth.

47
Q

how is active transport useful for us?

A

stops us from starving

48
Q

how does active transport stop us from starving?

A

when there is a higher conc of glucose and amino acids, they diffuse naturally. BUT when theres a lower conc of nutrients in the gut than blood the conc gradient is the wrong way(blood conc should be lower), so active transport allows allows nutrients to go into blood by putting glucose into the bloodstream to be transported to cells for respiration

49
Q

when do cells use diffusion?

A

to take in substances that are needed and get rid of waste products

50
Q

what does a SA:volume ratio show?

A

the larger an organism, the smaller its SA in comparison to its volume

51
Q

how do single celled organisms diffuse?

A

gases and dissolved substances difuse in/out of the cells across the membrane because they have a large SA compared to volume

52
Q

how do multicellular organisms diffuse?

A

they have a smaller SA compared to volume so not enough can diffuse from the outer surfaces to supply the entire volume

53
Q

how are exchange surfaces adapted?

A

thin membrane - short distance to diffuse
large surface area - lots of substances can diffuse at once
animals have lots of blood vessels - in/out blood fast

54
Q

what is the job of the lungs?

A

transfer o2 to blood

remove co2 which is done by alveoli

55
Q

alveoli features

A

large SA
moist lining for dissolving gases
thin walls
good blood supply

56
Q

where is the villi found?

A

small intestine

57
Q

what does villi do?

A

increase the SA so that digested food is aborbed faster into the blood

58
Q

features of villi?

A

single layer of surface cells
good blood supply - assist fast absorption

59
Q

how is a leaf structured to enable photosynthesis?

A

stomata - co2, water vapour, o2 (from photosynthesis) diffuses through
guard cells - control size of stomata by closing so water isnt lost, plant would wilt
flat shape - large SA, more effective
cell wall - has air spaces that increase SA, co2 is more likely to get in

60
Q

what are gills?

A

gas exchange surface in fishes

61
Q

how do gills help with diffusion?

A

water containing o2 enters through the mouth and passes through the gills. o2 diffuses from the water into the blood in the gills and co2 diffuses from the blood into the water

62
Q

features of gills?

A

made of gill filaments - big SA for gas exchange
gill filaments covered in lamellae - increase SA
lamellae has lots of capilillaries - speed up diffusion
thin surface layer of cells - minimise distance gases need to diffuse

63
Q

what are the parts of a plant and its functions?

A

waxy cuticle (waterproof layer) - stops water from evaporating
spongey mesophyll (holes -> large SA -> maximise diffusion) - gas exchange
palisade mesophyll (chloroplasts) - photosynthesis
guard cells - control size of stomata (what comes in/out)

64
Q

what is the word and symbol equation for aerobic respiration?

A

glucose + oxygen -> carbon dioxide + water
C6H12O6 + 6O2 → 6CO2 + 6H2O

65
Q

what is the word and symbol equation for photosynthesis?

A

carbon dioxide + water -> glucose + oxygen
6CO2 + 6H2O → C6H12O6 + 6O2

66
Q

what is an organelle?

A

a small structure within a cell membrane and has a function

67
Q

what does bacteria multipy through?

A

binary fission

68
Q

what is binary fission?

A

type of asexual reproduction - number doubles every 10 minutes

69
Q

what does inverse square law tell us?

A

Light intensity follows an inverse square relationship - if you double the distance from the light source, the intensity quarters.

70
Q

give an example of metabolism?

A

respiration - breaking down nuterients
conversion of glucose and starch
breakdown of excess protein

71
Q

what is a control variable?

A

the variable you don’t change

72
Q

which variable do you measure?

A

dependant

73
Q

what is an independant variable?

A

the one you change