Cell biology Flashcards

1
Q

Name 5 subcellular structures that both plant and animal cells have.

A
Nucleus
Cell membrane
Mitochondria
Ribosomes
Cytoplasm
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2
Q

What three things do plant cells have that animal cells don’t?

A

Cell wall
Chloroplasts
Vacuole

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3
Q

Where is genetic information stored in an animal cell?

A

Nucleus

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4
Q

Where is genetic information stored in a bacteria cell?

A

In the single cellular strand of DNA that floats freely in the cytoplasm

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5
Q

What is a prokaryotic cell? Give an example.

A

Small, simple cells e.g. bacteria

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6
Q

What is a eukaryotic cell? Give an example.

A

Larger, complex cells e.g. animal and plant cells

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7
Q

What gives higher resolution - a light microscope or an electron microscope?

A

Electron microscope

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8
Q

What is cell differentiation?

A

When a stem cell develops into a specialised cell

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9
Q

Give three ways that a sperm cell is adapted for swimming to an egg cell.

A

Streamline head
Tail
Contains a lot of mitochondria for energy

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10
Q

What are chromosomes?

A

Coiled up lengths of DNA molecules that contain genetic information

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11
Q

What is the cell cycle?

A

The process where cells divide It makes new cells for growth, development and repair

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12
Q

How can embryonic stem cells could be used to cure disease.

A

Embryonic stem cells can turn into any type of cell, unlike stem cells found in bone marrow. This means that the embryonic stem cells can be used to make clones of specialised cells.

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13
Q

Why might people oppose the use of embryonic stem cells?

A

For ethical reasons.

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14
Q

What is diffusion?

A

The change from an area of high concentration to low concentration.

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15
Q

Name three substances that can diffuse through cell membranes.

A

Amino acids
Water
Oxygen
Glucose

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16
Q

Name two substances that cannot diffuse through cell membranes.

A

Protein

Starch

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17
Q

What type of molecules move by osmosis?

A

Water

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18
Q

What is active transport?

A

The change of an area of low concentration to high concentration.

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19
Q

What is the function of a cell wall?

A

Provides structure, strength and support.

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20
Q

What is the function of the cell membrane?

A

Controls substances in and out of the cell

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21
Q

What is the photosynthesis word equation?

A

Carbon dioxide + water > glucose + oxygen

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22
Q

What is transpiration?

A

The loss of water in a plant.

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23
Q

What is the function of the upper epidermis?

A

It is transparent to let light to pass through to the palisade layer

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24
Q

Where is bile produced and what is its function?

A

It is produced in the liver and it neutralises stomach acid and emulsifies fats.

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25
Q

What is the function of cytoplasm?

A

Most chemical reactions take place here. It is controlled by enzymes

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26
Q

What is the function of the lower epidermis?

A

It has stomata controlled by guard cells; efficient gas exchange

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27
Q

What is the function of ribosomes?

A

Protein synthesis takes place here

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28
Q

What is the function of a permanent vacuole?

A

Stores cell sap and keeps the cell turgid

29
Q

What is the function of the palisade layer?

A

It has many chloroplasts where photosynthesis takes place

30
Q

What is the function of chloroplasts?

A

It contains green pigment called chlorophyll and photosynthesis takes place here

31
Q

What is the function of the waxy cuticle?

A

Reduces water loss

32
Q

What is the function of the mitochondria?

A

Provides energy through respiration

33
Q

name 5 plant tissues

A
The upper and lower epidermal tissue
The palisade mesophyll tissue
The spongy mesophyll tissue
Air space
The waxy cuticle
Stomata
Guard cells
34
Q

What are the functions of xylem and phloem

A

They deliver water and nutrients to entire cell

Go takeaway glucose produced in photosynthesis

35
Q

What is the function of the nucleus

A

Stores genetic information and controls the activities of the cell

36
Q

What is respiration?

A

The transfer of energy from the breakdown of glucose

37
Q

Where is genetic information stored in a prokaryotic cell

A

It is floating freely in the cells and isn’t in the nucleus

38
Q

Where is genetic information stored in a eukaryotic cell

A

Nucleus

39
Q

Define the term magnification.

A

The amount you can enlarge an image. Eg. an electron microscope has a higher magnification than a light microscope

40
Q

Define the term resolution.

A

How sharp the image is. Higher resolution means a clearer, sharper image.

41
Q

What can you use a light microscope to look at? What are the advantages?

A

Individual cells and large subcellular structures such as the nucleus.
It is advantageous to use a light microscope as they’re cheaper and easier to move.

42
Q

What can you use a electron microscope to look at? What are the advantages?

A

Tiny subcellular structures such as mitochondria, ribosomes and plasmids.
This is why its advantageous to use this type of microscope. It also has a higher resolution.

43
Q

What is the equasion for magnification?

A

Image size divided by real size

44
Q

How could you prepare a slide when using a light microscope?

A

If you were looking at the epidermal tissue of an onion you would add a drop of wateronto the centre of a clean slide. Then place the epidermal tissue on the water using tweezers. Then add a drop of iodine solution to the tissue and place a cover slip over the top trying to avoid getting air bubles.

45
Q

What does the term differentiation mean?

A

The process in which an unspecialised cell changes into a specialised cell.

46
Q

Why do cells need to be specialised?

A

To allow them to carry out different functions. The cell is adapted to carry out a particular function.

47
Q

What are undifferentiated cells called? Where would you find them?

A

Stem cells

Found in human bone marrow and in embryos

48
Q

Pick two specialised animal cells. State their function and describe how it is adapted to carry out this function.

A

A sperm cell fertilised the egg after intercourse. The sperm cell has a long tail, streamline head and lots of mitochondria to provide energy. It also carries enzymes in its head to help digest through the egg’s cell membrane.
Red blood cells transport oxygen and waste products to and from the lungs and body. It doesn’t have a nucleus to optimise the amount that can be carried and it also has a large surface area to insrease the diffusion rate.

49
Q

Pick two specialised plant cells. State their function and describe how it is adapted to carry out this function.

A

A root hair cell absorbs water and minerals. Their shape increases the surface are of the cell for faster absorption.
Xylem cells are specialised for transporting substances. The xylem cells are hollow in the centre so that stuff can flow through.

50
Q

Why are stem cells useful to us?

A

We can make specialised cells out of stem cells to use in medicine or research.

51
Q

What are arguments for using stem cells?

A

They can be used to treat disease eg. replace faulty blood cells.
They can be used to replace faulty cells in sick people eg. insulin producing cells for people with diabetes, they can replace nerve cells for people with spine injuries etc.
Embryonic stem cells used in this research are usually unwanted ones from fertility clinics and if they weren’t used for this, they would usually be destroyed.

52
Q

What are arguments against using stem cells?

A

Some people believe it’s wrong to use embryonic stem cells as it is a potential human life.

53
Q

How do body cells divide?

A

Cell division is part of the cell cycle. The part where it actually divides is called mitosis.

54
Q

Define the term difusion.

A

The movement of substances from a high to low concentration along the concentration gradient.

55
Q

What can increase the rate of diffusion?

A

The surface area.
A larger concentration gradient.
Higher temperature (more energy)

56
Q

Difine the term osmosis.

A

The movement of water molecules accross a partially permeable membrane from a region of higher water concentration to lower water concentration.

57
Q

What kind of moleculecan be transported by osmosis?

A

water

58
Q

Describe how water moves by osmosis

A

Water molecules pass through the membrane but larger molecules (such as sucrose) can’t as the molecules are too big. The membrane will aim to ‘even up’ the concentration of water molecules on each side of the membrane.

59
Q

Define the term active transport

A

Substances absorbed against the concentration gradient from a low concentration to high concentration.

60
Q

Give an example of active transport in plants.

A

Root hair cells. Minerals are absorbed from a low concentration in the soil to a high concentration the the root hair cell.

61
Q

Give an example of active transport in animals.

A

Nutrients are transported through active transport from a low concentration in the gut to a higher concentration of nutrients in the blood.

62
Q

What does the SA to volume ratio tell us?

A

It tells us how easily stuff moves between the organism and its enviroment.

63
Q

How do you calculate SA to volue ratio?

A

Work out the surface area then the volume and put it into ratio form and cancel it down.

64
Q

Why do multicellular organisms need specialised exchange surfaces?

A

To ensure substances diffuse through them in the most effective way. Multicellular organisms have a smaller surface area to volume ratio so not enough substances can be diffused from their outside surface to supply their entire volume.

65
Q

Why don’t single-celled organisms need specialised exchange surfaces?

A

Gases and substances can diffuse directly into/out of the cell across the cell membrane. This is because they have a large SA to volume ratio.

66
Q

Describe how gas exchange takes place in the lungs.

A

Air is breathed into the lungs through the bronchiole. CO2 is diffused out of the red blood cells into the alveoli. The air is breathed into the alveoli and oxygen is diffused into the red blood cells through the thin walls (one cell thick).

67
Q

How have alveoli been adapted for efficient gas exchange?

A

Large surface area
Moist lining (to dissolve gases)
Very thin walls
A rich blood supply

68
Q

Describe how gas exchange takes place in the small intestine.

A

The small intestine is covered in millions of villi which increase the surface area in a big way. This means that digested food is absorbed much more quickly into the blood.

69
Q

How are villi in the small intestine adapted to increase the rate of substance exchange?

A

Single layer of surface cells

A very good blood supply for quick absorption