B1 Cell biology Flashcards

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1
Q

what subcellular structures are in an animal cell?

A
  • nucleus
  • cytoplasm
  • cell membrane
  • mitochondria
  • ribosomes
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2
Q

what subcelluar structures are in a plant cell?

A
  • nucleus
  • cytoplasm
  • cell membrane
  • mitochondria
  • ribosomes
  • rigid cell wall
  • permanent vacuole
  • chloroplasts
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3
Q

describe the nucleus

A

contains genetic material that controls the activities of the cell

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4
Q

describe the cytoplasm

A

gel-like substance where most of the chemical reactions happen
it contains enzymes that control these chemical reactions

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5
Q

describe the cell membrane

A

this holds the cell together and controls what goes in and out

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6
Q

describe mitochondria

A

most of the reactions for aerobic respiration takes place

respiration transfers energy that the cell needs to work

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7
Q

describe ribosomes

A

this is where proteins are made in the cell

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8
Q

describe the rigid cell wall

A

made of cellulose

it supports the cell and strengthens it

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9
Q

describe the permanent vacuole

A

contains cell sap, a weak solution of sugars and salts

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10
Q

describe chloroplasts

A

where photosynthesis occurs, which makes green substance called chlorophyll, which absorbs the light needed for photosynthesis

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11
Q

what are eukaryotic cell?

A

eukaryotes are organisms that are made up of eukaryotic cells

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12
Q

what are prokaryote cells?

A

it is a prokaryotic cell (its a single-celled organism)

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13
Q

what cell is bacteria?

A

bacteria is prokaryotes

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14
Q

what subcellular structures does bacteria contain?

A
  • cell membrane
  • single circular strand of DNA that floats freely in the cytoplasm (doesn’t have a nucleus)
  • small rings of DNA called plasmids
  • cell wall
  • cytoplasm
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15
Q

what is the equation for magnification?

A

magnification = image size / real size

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16
Q

what is differentiation?

A

the process by which a cell changes to become specialised for its job
as cells change, they develop different subcellular structures and turn into different types of cells

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17
Q

give examples of specialised cells

A
  • sperm cells
  • nerve cells
  • muscle cells
  • root hair cells
  • phloem and xylem cells
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18
Q

what are sperm cells specialised for?

A

reproduction

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19
Q

what are nerve cells specialised for?

A

rapid signalling

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20
Q

what are muscle cells specialised for?

A

contraction

21
Q

what are root hair cells specialised for?

A

absorbing water and minerals

22
Q

what are phloem and xylem cells specialised for?

A

transporting substances

23
Q

describe the function of sperm cells

A

to get the male DNA to the female DNA
it has a long tail and a streamlined head to help it swim to the egg
there are lots of mitochondria in the cell to provide the energy needed
it also carries enzymes in its head to digest through the egg cell membrane

24
Q

describe the function of nerve cells

A

to carry electrical signals from one part of the body to another. these cells are long (to cover more distance) and have branched connections at there ends to connect to other nerve cells and form a network throughout the body

25
Q

describe the function of muscle cells

A

to contact quickly
these cells are long (so they have space to contract) and contain lots of mitochondria to generate the energy needed for contraction

26
Q

describe the function of root hair cells

A

root hair cells are cells on the surface of plant roots, which grow into long “hairs” that stick out into the soil
this gives the pants big surface area for absorbing water and mineral ions from the soil

27
Q

describe the function of phloem and xylem cells

A

from phloem and xylem tubes, which transport substances such as food and water around plants. to form the tubes, the cells are long and joined end to end. xylem cells are hollow in the centre and phloem cells have very few subcellular structures, so that stuff flow through them

28
Q

what is diffusion?

A

it is the spreading out of particles from an area of higher concentration to an area of lower concentration

29
Q

what is osmosis?

A

the movement of water molecules across a partially permeable membrane from a region of higher water concentration to a region of lower water concentration

30
Q

how many chromosomes do body cells have?

A

they normally have 2 copies of each chromosome - one from the organisms mother and one from its father

31
Q

what is the cel cycle?

A

body cells on multicellular organisms divide to produce new cells as part of a series called the cell cycle

32
Q

what is mitosis?

A

the stage of the cell cycle when the cell divides

33
Q

what are the 2 main stages of the cell cycle?

A
  • growth and DNA replication

- mitosis

34
Q

growth and DNA replication is the fist part of the cell cycle
describe this

A

1) DNA is spread out in long strings
2) before it divides, the cell has to grow and increase the amount of subcellular structures such as mitochondria and ribosomes
3) it duplicates its DNA - one copy for each cell. the DNA is copied and forms X shaped chromosomes. each “arm” of the chromosomes is an exact duplicate of the other

35
Q

mitosis is the second part of the cell cycle

describe this

A

once it has gone through growth and DNA replication
its ready for mitosis…
1) chromosomes line up and cell fibres pull hem apart. the 2 arms of each chromosomes go to the opposite ends of the cell
2) membranes form around each of the sets of chromosomes. these become the nuclei of the 2 new cells - the nucleus is divided
3) lastly, the cytoplasm and cell membrane divide. the cell has now produced two new daughter - contain the same DNA - identical. their DNA is also identical to the parent cell

36
Q

what does medicine already use adult stem cells for?

A

to cure disease

37
Q

where does diffusion happen?

A

in both solutions and gases- because the particles in these substances are free to move about randomly

38
Q

the bigger the concentration gradient (the difference in concentration) ……

A

the faster the diffusion rate

39
Q

a higher temperature will ……

A

give a faster diffusion because the particles have more energy, s move around faster

40
Q

how is the cell membrane clever?

A
  • the hold the cell together but they let suff in and out as well
  • dissolved substances can move in and out of cells by diffusion
41
Q

what is the job of the lungs?

A

it is to transfer oxygen to the blood and to remove waste carbon dioxide from it
to do this the lungs contain millions of little air sacs called alveoli where gas exchange takes place

42
Q

when is active transport used in the gut?

A

when there is a lower concentration of nutrients in the gut but a higher concentration of nutrients in the blood

43
Q

when does active transport diffuse naturally into the blood?

A

when theres a higher concentration of glucose and amino acids in the gut

44
Q

what happens when the active transport concentration gradient is the wrong way?

A

when theres a lower concentration of nutrients in the gut than there is in the blood

45
Q

describe root hair cells

A
  • cells on the plant roots grow into “hairs” which stick out into the soil
  • each branch covers millions of these microscopic hairs
  • means there is a large surface are for absorbing water and mineral ions from the soil
  • plants need mineral ions for healthy growth
  • concentration of minerals is usually higher in the root hair cells than in the soil around them
46
Q

describe the practical of the effect of sugar solutions on plant tissue

A
    • cut into potato into identical cylinders
      - beakers with different sugar solutions in them
      - one should be pure water and a very concentrated sugar solution
    • measure mass of cylinder, then leave one cylinder in each beaker for 24 hours
      3) - take them out, dry with paper towel and measure masses again

4) - cylinders have drawn in water by osmosis = increased in mass
- water has been drawn out = decreased in mass
- calculate percentage change in mass, plot graphs

5) dependent variable = chip mass
independent variable = concentration of the sugar solution
- all of variables must be kept the same in each case or the experiment won’t be a fair test
- may be some errors, reduce the effect of these errors by repeating the experiment and calculating a mean percentage change at each concentration

47
Q

how are the alveoli specialised?

A
to maximise the diffusion of oxygen and carbon dioxide 
they have: 
- an enormous surface area 
- a moist lining for dissolving gases
- very thin walls
- a good blood supply
48
Q

what is inside the small intestine?

A

covered in millions and millions of these tiny little projections called villi
- increase surface area so that digested food is absorbed much more quickly into the blood

they have:

  • a single layer of surface cells
  • a very good blood supply to assist quick absorption