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Cell Biology Flashcards

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AP® Biology flashcards Biology 101 flashcards
1
Q

what’s the difference between eukaryotes and prokaryotes?

A

 eukaryotes are made up of eukaryotic cells, and prokaryotes are made up of a prokaryotic cell (its a single celled organism)

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2
Q

What are the different parts of a cell called?

A

Subcellular structures

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3
Q

What is a nucleus?

A

It contains the genetic material of the controls the activities of a cell.

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4
Q

What is cytoplasm?

A

Gel like substance where most of the chemical reactions happen. It contains enzymes.

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5
Q

What is a cell membrane?

A

It holds the cell together and controls what goes in and out.

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6
Q

What is mitochondria?

A

This is where most of the reactions for aerobic respiration take place. Respiration transfers energy of the cell needs to work.

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7
Q

What are ribosomes?

A

These are where are proteins made.

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8
Q

What is a cell wall?

A

Made of cellulose, it supports the cell and strengthens it.

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9
Q

what are chloroplasts?

A

These are where photosynthesis occurs, which makes food for the plant. They contain a green substance called chlorophyll which absorbs the light needed.

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10
Q

What is a permanent vacuole?

A

It contains cell sap, a week solution of sugar and salt.

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11
Q

Name a prokaryote.

A

Bacteria.

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12
Q

Does bacteria have a nucleus?

A

No. They have a single circular strand of DNA that floats freely in the cytoplasm. They may also contain small rings of DNA called plasmids.

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13
Q

What does subcellular structures do animal cells have?

A

A nucleus, cytoplasm, cell membrane, ribosomes, and mitochondria

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14
Q

What is subcellular structures do plant cells have that animal cells don’t?

A

 Permanent vacuole, a rigid cell wall, and chloroplasts.

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15
Q

What does sub cellular structures do bacteria cells have?

A

Cell membrane, cell wall, single strand of DNA, plasmids and cytoplasm.

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16
Q

how do light microscopes see?

A

They use light and lenses to form an image of a specimen and magnify it.

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17
Q

How do Electron microscopes work?

A

they use electrons instead of light to make an image, they have a much higher magnification.

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18
Q

What is the formula for magnification

A

magnification= image size
—————
real size 

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19
Q

How do you convert micrometers into millimetres?

A

Divided by 1000.

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20
Q

What are the different parts of a light microscope?

A

The eyepiece, high and low power objective lenses, course adjustment knob, fine adjustment knob (smaller one), light and stage

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21
Q

how would you prepare the slide of a microscope to view an onion cell?

A

The first is a drop of water to the middle of a clean slide
Cut up and onion in separate into layers, use tweezers to peel off some of the epidermal tissue
Place the epidermal tissue onto the water
Add a drop of iodine solution (this highlights objects in a cell by adding colour to them)
Then place the cover slip on top.

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22
Q

What is cell differentiation?

A

The process by which a cell changes to become specialised for its job.

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23
Q

Why does most differentiation happen before or as an organism is developing?

A

because after your cells have become specialised they lose the ability to differentiate.

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24
Q

what are cells that can differentiate in mature animals most used for?

A

repairing and replacing cells.

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25
Q

what are undifferentiated cells called.?

A

Stem cells.

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26
Q

How are sperm cells specialised for reproduction?

A

it has a long tail and a streamlined head to help it swim to the egg.
it also has lots of mitochondria to provide the energy needed.
It also carries enzymes as it’s hard to digest through the egg cell membrane.

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27
Q

How are nerve cells specialised for rapid signalling?

A

They are long and have branched connections at their ends to connect to other nerve cells and form a network.

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28
Q

How are muscle cells specialised for contraction?

A

The cells are long and contain lots of mitochondria to generate the energy needed for contraction.

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29
Q

how are root hair cells specialised for absorbing water and minerals?

A

Root hair cells are on the surface of a plants roots and they grow out and stick into the soil. They have a big surface area for absorbing water and mineral oils.

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30
Q

How are phloem and xylem cells specialised for transporting substances?

A

phloem and xylem Cells form phloem and xylem tubes which transports food and water around the plant.
To form tubes the cells are long and join end to end.
Xylem cells are hollow in the centre and phloem cells have very few subcellular structures said that stuff can flow through them.

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31
Q

Why are embryonic stem cells so special?

A

Because they can turn into any kind of cell.

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32
Q

What is one of the few places you can find a stem cell in adults?

A

Bone marrow.

33
Q

give an example of how adult stem cells can be used in medicine.

A

you can use the stem cells of a healthy persons bone marrow and replace faulty blood cells in someone who needs them.

34
Q

How can you stop rejection of stem cells in somebody’s body?

A

therapeutic cloning, which would make the cells have the same genetic information as a patient.

35
Q

What are the risks involved in stem cell research?

A

stem cells growing in the lab may become contaminated with a virus that could be passed on to a patient. 

36
Q

Why are some people against stem cell research?

A

They believe that human embryos shouldn’t be used for experiments seeing as it is a potential human right life.

37
Q

Where are stem cells found in plants?

A

Meristems, these cells can differentiate into any type of plant cell.

38
Q

What can the stem cells be used for?

A

They can be used to produce clones plants quickly and cheaply, these can help with endangered species.

39
Q

Why are stem cells useful for farmers?

A

Because they can clone stem cells used to grow crops that have desired features for farmers e.g. disease resistance.

40
Q

What is the role of chromosomes?

A

They contain genetic information.

41
Q

What are chromosomes?

A

Coiled up lengths of DNA molecules.

42
Q

How many pairs of chromosomes are in a human cell?

A

23.

43
Q

Why do people have two copies of each chromosome?

A

Because they get one from their mother in one from the father.

44
Q

what do genes do?

A

Different genes control the development of different characteristics e.g. hair colour.

45
Q

What is mitosis?

A

mitosis is cell division.

46
Q

Why is mitosis important?

A

Because it grows and develops or replaces cells that have been damaged.

47
Q

What does the cell cycle end in?

A

Two new cells identical to the original so, with the same number of chromosomes.

48
Q

What does a cell have to do before it divides?

A

For divides, so has to grow and increase the amount of sub cellular structures e.g. mitochondria and ribosomes. And duplicated DNA so there is one copy for each new cell. DNA is copied in forms X shaped chromosomes.

49
Q

What happens during mitosis?

A

The chromosomes lineup at the centre of the cell and cell fibres pull them apart. The two arms of each chromosome go to opposite ends of the cell.
Membranes form around each of the sets of chromosomes. These become the nuclei of the two new cells.
Lastly the cytoplasm and cell membrane divide. The cell now has two new daughter cells containing exactly the same DNA.

50
Q

What is diffusion?

A

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

51
Q

Why will places of a high temperature have a faster diffusion rate?

A

Because the particles have more energy to move around faster.

52
Q

What can and can’t diffuse into cells?

A

Things like glucose, oxygen, amino acids in water can. Big molecules like starch and protein can’t fit through the membrane.

53
Q

The larger surface area of the membrane…

A

The fast of the diffusion rate because more particles can pass through at once.

54
Q

What is osmosis?

A

The movement of water molecules across a partially permeable (small holes) membrane from a region of high water concentration to a region of lower water concentration.

55
Q

What is the practical experiment on a serving the effect of sugar solution implant shoe?

A

You can use potato bits the same size and put them into beakers difference of sugar solutions, one should have no sugar and just water another should have a very high concentration of sugar and then some in between. You can measure the mass of the potatoes and then leave them for the same amount of time, when you take them out measure the masses again. The potatoes that have drawn in water by osmosis should have increased in mass however the ones the water has been drawn out of should’ve decreased.

56
Q

What is active transport?

A

When substances need to be absorbed against a concentration gradient i.e. from a lower concentration to high concentration.

57
Q

Why do Root hair cells need active transport?

A

Because they need to absorb water and mineral ions from the soil even though they have a higher concentration of these things than the soil.

58
Q

How does active transport stop us from starving?

A

Because even though usually there is a high concentration of glucose and amino acids in the gut, when there is lower concentration, active transport allows nutrients to be taken into the blood still.

59
Q

What is gas exchange?

A

When oxygen and carbon dioxide are transferred between cells and the environment.

60
Q

How easy it is for an organism to exchange substances between cells and the environment depends on what?

A

The organisms surface area to volume ratio.

61
Q

The larger an organism is…

A

The smaller the surface area is compared to its volume.

62
Q

Why in single celled organisms, can gases and self substances diffuse directly into the cell across the membrane?

A

because they have a large surface area compared the volume, so enough substances can be exchanged across the membrane to supply the volume of the cell.

63
Q

Why do multicellular organisms need some sort of exchange surface for efficient diffusion?

A

Because they have a smaller surface area compared to the volume therefore not enough substances confuse from outside to supply their entire volume.

64
Q

What do exchange surfaces need to maximise effectiveness?

A

They need a thin membrane so substances only have a short distance to diffuse.
They have a large surface area so lots of a substance can diffuse at once.
Gas exchange surfaces in animals often ventilated too (air moves in and out).

65
Q

What do lungs have to be able to transfer oxygen to the blood and to remove carbon dioxide from it?

A

The lungs contain millions of little air sacs called alveoli where gas exchange takes place.

66
Q

What do alveoli in the lungs have to maximise the diffusion of oxygen and CO2?

A

They have an enormous surface area.
They have a moist lining for dissolving gases.
They have very thin walls and a good blood supply.

67
Q

Why is the small intestine covered in millions of Villi?

A

Because they increase the surface area so that digested food is absorbed much quicker into the blood.

68
Q

how are Villi structured?

A

they have a single layer of surface cells and a very good blood supply (Network of capillaries) to assist quick absorption.

69
Q

What are the holes in a leaf which carbon dioxide diffuse through?

A

They are called stomata. Oxygen and water vapour also diffuse out through the stomata.

70
Q

What is the size of the stomata controlled by?

A

Guard cells.

71
Q

What do the guard cells do?

A

they close the stomata if the plant is losing water faster than it is being replaced by the roots.

72
Q

Why is the flattened shape of the leaf important?

A

Because it increases the area of this exchange surface so that is more effective.

73
Q

Why do leaves have air spaces on the inside?

A

Because it increases the area of the exchange surface (Made from the walls of the cell inside the leaf), this means there is more chance for carbon dioxide to get into the cells. 

74
Q

How does water vapour escape a leaf?

A

diffusion.

75
Q

What are the gas exchange surfaces in fish?

A

The gills

76
Q

How to gills work?

A

Water (containing oxygen) enters the fish through its mouth and passes out through the girls. As this happens, oxygen defuses from the water into the blood in the girls and carbon dioxide diffuses from the blood into the water.

77
Q

What do girls have that give them a big surface area for gas exchange?

A

Gill filaments, these are lots of thin plates. 

78
Q

What do the llamellae on gills have to help them speed up diffusion?

A

they have lots of blood capillaries to speed up diffusion.
Also have a thin surface layer of cells to minimise the distance the gases have to diffuse. 

Biology (9 decks)

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