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Cell Biology Flashcards

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AP® Biology flashcards Biology 101 flashcards
1
Q

eukaryotic cell

A

plant and animal cells, have a cell membrane, cytoplasm and genetic material enclosed in a nucleus

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2
Q

prokaryotic cells

A

bacterial cells are much smaller, have a cytoplasm and cell membrane surrounded by a cell wall, genetic material isn’t enclosed in a nucleus

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3
Q

plasmids

A

one or more small rings of DNA

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4
Q

what do most animal cells have

A

nucleus
cytoplasm
cell membrane
mitochondria
ribosomes

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5
Q

what are sperm cells specialised for and how are they adapted?

A

They join with an egg cell during
fertilisation to form an embryo.
A tail moves them towards an egg cell.Many mitochondria
release energy for movement.
Part of the tip of the head of the sperm, called the acrosome, releases enzymes to digest the egg membrane to allow fertilisation to take place.
The haploid nucleus contains the genetic material for fertilisation.
Sperm are produced in large numbers to increase the chance of fertilisation.

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6
Q

what are nerve cells specialised for and how are they adapted?

A

Nerve cells transmit electrical signals in the nervous system.
They are thin, and can be more than one metre long in your spinal cord. This means they can carry messages up and down the body over large distances very quickly.Nerve cells have branched connections at each end. These join other nerve cells, allowing them to pass messages around the body.They have a fatty (myelin) sheath that surrounds them this increases the speed at which the message can travel.

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7
Q

what are muscle cells specialised for and how are they adapted?

A

Muscles cells are found in bundles which make up our muscles. These cells are able to contract and relax (return to original length).Cardiac (heart) muscle cells contract and relax to pump blood around our bodies for our entire lives. They never get tired.Smooth muscle cells make up thin sheets of muscle, such as the stomach lining. They can also be arranged in bundles, or rings, like that in the anus. Skeletal muscle is joined to bones. Its cells contract to make bones move and joints bend.

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8
Q

what are root hair cells specialised for and how are they adapted?

A

Roots hold plants in place as they grow and also absorb water and minerals from the soil. The outside surface of roots are covered with root hair cells, which have tiny ‘hairs’ which poke into the soil. This massively increases the surface area for the root hair cell to absorb more water and minerals.

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9
Q

what are xylem cells specialised for and how are they adapted?

A

Xylem cells transport water from the roots to other parts of the plant. Xylem cells run inside stems of plants from their roots to their leaves. Xylem cells die and their ends break down. This allows them to form long tubes to carry water upwards for photosynthesis. They have thick cell walls to provide support to the plant. This holds the leaves up for photosynthesis and the flowers up for reproduction.

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10
Q

what are phloem cells specialised for and how are they adapted?

A

Phloem cells transport sugary water from the leaves to the rest of the plant. Phloem cells are alive. Next to the phloem cells are companion cells which have many mitochondria. Here
respiration occurs to release energy from glucose to transport sugar and other substances in the phloem.

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11
Q

cell specialization

A

they develop as the organism does in order to perform a specific function

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12
Q

cell differentiation

A

the process where which a cell becomes specialised

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13
Q

when can most animal cells differentiate?

A

at an early stage

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14
Q

when can most plant cells differentiate?

A

throughout life

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15
Q

in mature animals what is cell division restricted to

A

repair and replacement

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16
Q

1590s - Dutch spectacle makers Janssen

A

experimented with putting lenses in tubes. They made the first compound microscope thought to have magnified from ×3 to ×9.

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17
Q

1650 - British scientist, Robert Hooke

A

observed and drew cells using a compound microscope.

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18
Q

Late 1600s – Dutch scientist Antonie van Leeuwenhoek

A

constructed a microscope with a single spherical lens. It magnified up to ×275

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19
Q

1800s microscopes

A

the optical quality of lenses increased and the microscopes are similar to the ones we use today.

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20
Q

how has electron microscopy increased our understanding of sub-cellular structures

A
  • much higher magnification and resolving power
  • cells can be studied in much finer detail
  • biologists can see much more sub-cellular structures
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21
Q

magnification =

A

size of image ÷ size of real object

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22
Q

convert 3mm into micro meters

A

3000 μm

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23
Q

convert 4.5mm into nano meters

A

4,500,000 nm

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24
Q

how do bacteria multiply and how often

A

binary fission and 20mins

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25
Q

area of circle

A

pi × radius²

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26
Q

name 2 ways bacteria can be grown

A

nutrient broth solution or as colonies on an agar gel plate

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27
Q

how to prepare uncontaminated culture using an aspetic technique

A
  • petri dish and culture must be sterilised
  • inoculating loops used to transfer microorganisms to media must be sterilised by passing them through a flame
  • the lid of the petri dish should be sealed with adhesive tape and stored upside down
  • in schools microorganisms should stored at 25 degree Celsius
28
Q

write 19200 in standard form

A

1.92 ×10^4

29
Q

what is in the nuecleus

A

chromosomes made of DNA molecules. each chromosome carries a large number of genes.

30
Q

how many chromosomes are found together in body calls?

A

pairs

31
Q

what is the cell cycle

A

cell division in a series of stages

32
Q

during the cell cycle the genetic material is ________ and then ________ into two _________

A

doubled, divided, identical cells

33
Q

what does a cell have to do before it divides

A

increase number of sub-cellular structures such as ribosomes and mitochondria

34
Q

the DNA replicates to form what?

A

two copies of each chromosome

35
Q

in mitosis one set of each chromosome is…

A

pulled to each end of the cell and the nucleus divides

36
Q

what is the last part of the cell cycle?

A

cytoplasm and cell membranes divide to form two identical cells

37
Q

cell division by mitosis is important for what?

A

growth and development of multicellular organisms

38
Q

stem cell

A

an undifferentiated cell of an organism which is capable of giving rise to many more cells of the same type and from which certain other cells can arise from differentiation

39
Q

what is the function of stem cells in an embryo?

A

can be used to turn into any type of cell

40
Q

what is the function of stem cells in adult animals?

A

to grow or replace specialised tissue

41
Q

what is the function of stem cells in meristems in plants?

A

allows plants to grow for their whole lives

42
Q

stem cells from human embryos can be used for what?

A

cloned and made to differentiate into most different types of human cells

43
Q

give one example of what stem cells from adult bone marrow can form?

A

blood cells

44
Q

what conditions can treatment with stem cells be able to help?

A

diabetes and paralysis

45
Q

what are the downsides of using stem cells as treatment

A

transfer of viral infection, and some people have ethical or religious objections

45
Q

why is the embryo is produced with the same genes as the patient

A

so the patient’s body doesn’t reject it

46
Q

what can stem cells from meristems be used for?

A

rare species can be cloned from extinction, crop plants with special features such as disease resistance can be cloned to produce large numbers of identical plants for farmers

47
Q

diffusion

A

the spreading out of particles of any substance in solution, or gas particles, resulting in a net movement form an area of high concentration to an area of lower concentration

47
Q

examples of diffusion in body cells

A
  • oxygen and carbon dioxide in gas exchange
  • waste product of urea cells into blood plasma
48
Q

factors that effect the rate of diffusion

A

concentration gradient, the temperature, the surface area of the membrane

49
Q

the effectiveness of exchange surface is increased by

A
  • large surface area
  • membrane is thin
  • efficient blood supply in animals
  • being ventilated
50
Q
A
  • These drinks are designed to help replace water, salts (ions/electrolytes) and glucose lost from the body during exercise
    If there is too little water in the blood or the blood ion concentration is too high: cells will lose too much water by osmosis and shrink/dehydrate
    If the concentration of water in the blood is too high or the ion concentration is too low, cells will absorb too much water, swelling and possibly bursting
51
Q

what do isotoinc sport drinks contain and what are they used for?

A

contain similar concentrations of salt and sugar (glucose) as the human body and are primarily used for hydration and fluid replacement

52
Q

what happens if there is too little water in the blood or the blood ion concentration is too high

A

cells will lose too much water by osmosis and shrink/dehydrate

53
Q

what happens if the concentration of water in the blood is too high or the ion concentration is too low

A

cells will absorb too much water, swelling and possibly bursting

54
Q

what do hypertonic sport drinks contain and what are they used for?

A

contain concentrations of salt and sugar higher than typical blood levels
This provides high salt and sugar levels for absorption from the small intestine - these drinks are suitable for supplying glucose in particular during intense physical exercise

55
Q

what do hypotonic sport drinks contain and what are they used for?

A

contain concentrations of salt and sugar lower than typical blood levels
Drinking this type of drink creates a concentration gradient between the bloodstream and small intestine with the water potential in the small intestine being higher - these drinks are suitable for rapid re hydration as water is drawn into the bloodstream by osmosis

56
Q

how is the small intestine adapted for exchanging materials?

A

they have villi that increase the concentration gradient and are one cells thick, there is a rich blood supply to maintain a high concentration gradient

57
Q

how are the lungs adapted for exchanging materials?

A

alveolar are one cell think and increase the surface area, moist walls as gases dissolve

58
Q

how are gills in fish adapted for exchanging materials?

A

lamelle increase surface area and are one cell thick , the blood vessels are very close

59
Q

how are roots adapted for exchanging materials?

A

root hair cells have long thin projections that stick out into the soil, this massively increases the surface area

60
Q

how are leaves adapted for exchanging materials?

A

have a large surface area, they are thin so there is less for gases to travel,contain stomata, Cells are organised in layers within the leaf.

61
Q

osmosis

A

the diffusion of water from a dilute solution to a concentrated solution

62
Q

percentage gain =

A

initial - final divided by initial

63
Q

active transport

A

moves substances from a more dilute solution to a more concentrated solution

64
Q

explain the differences between diffusion osmosis and active transport

A
  • diffusion and active transport involve the movement of dissolved solutes, such as sugars or mineral ions, whereas - osmosis involves the transport of water only
  • in diffusion and osmosis, substances move down a concentration gradient.
  • active transport moves substances against a concentration gradient.
65
Q

what does active transport do in plants

A

sugar molecules to be absorbed from lower concentrations in the gut to blood, mineral ions to be absorbed into root hair cells from very dilute solutions

Biology (2 decks)

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