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GCSE Biology > Topic 1 - Key Concepts In Biology > Flashcards

Topic 1 - Key Concepts In Biology Flashcards

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1
Q

What are eukaryotic cells?

A

Cells that have a nucleus. They are more complex and include all animal and plant cells.

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2
Q

What are prokaryotic cells?

A

Cells that have no nucleus. These are smaller and simpler cells.

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3
Q

What is the function of a nucleus?

A

It contains the genetic material that controls the activities of the cell. Genetic material is arranged into chromosomes.

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4
Q

What is the function of the cytoplasm?

A

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

What is the function of the cell membrane?

A

Holds the cell together and controls what goes in and out.

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6
Q

What is the function of the mitochondria?

A

These are where most of the reactions for respiration take place. Respirations transfers energy that the cell needs to work.

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7
Q

What is the functions of the ribosomes?

A

These are involved in the translation of genetic material in the synthesis of proteins.

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8
Q

What is the function of the cell wall?

A

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

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9
Q

What is the function of the vacuole?

A

It contains sap and is a weak solution of sugar and salts. It maintains the internal pressure to support the cell wall.

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10
Q

What is the function of the chloroplasts?

A

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

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11
Q

What is the function of the chromosomal DNA?

A

It’s like one, long circular chromosome. It controls the cell’s activities and replication. It floats free in the cytoplasm not nucleus.

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12
Q

What is the function of the plasmid DNA?

A

Small loops of extra DNA that aren’t part of the chromosome. Plasmids contain genes for things like drug resistance, and can be passed between bacteria.

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13
Q

What is the function of the flagellum?

A

A long, hair-like structure that rotates to make the bacteria move. It can be used to move the bacteria away from harmful substances like toxins and towards beneficial things like nutrients to oxygen.

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14
Q

What is a multicellular organism?

A

An organism that contains lots of different types of cells (i.e. cells with different structures).

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15
Q

What is a specialised cell?

A

Cells that have a structure which makes them adapted to their functions.

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16
Q

What is a haploid cell?

A

A cell that only has a single set of unpaired chromosomes.

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17
Q

What are the main functions of the egg cell?

A

To carry the female DNA and nourish the developing embryo in early stages.

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18
Q

What are the 3 ways in which an egg cell is adapted to its functions?

A

1) It contains nutrients in the cytoplasm to feed the embryo.
2) It has a haploid nucleus.
3) Straight after fertilisation, its membrane changes structures to stop any more sperm getting in. This makes sure the offspring end up with the right amount of DNA.

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19
Q

What is the function of the sperm cell?

A

To transport the male’s DNA to the female’s egg.

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20
Q

What are the 4 ways in which a sperm cell is adapted to its function.

A

1) A sperm cell has a long tail so it can swim to the egg.
2) It has lots of mitochondria in the middle section to provide the energy (from respiration) needed to swim this distance.
3) It also has an acrosome at the front of the ‘head’, where it stores enzymes needed to digest its way through the membrane of the egg.
4) It also contains a haploid nucleus.

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21
Q

What is the function of a ciliated epithelial cell?

A

Moving materials.

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22
Q

What are the 4 ways in which a ciliated epithelial cell is adapted to its function?

A

1) Epithelial cells line the surface of organs.
2) Some of them have cilia on the top surface of the cell.
3) The function of the ciliated epithelial cells is to move substances - the cilia beat to move substances in one direction, along the surface of the tissue.
4) For example, the lining of the airways contains lots of ciliated epithelial cells. These help move the mucus (and all of the particles from the air that it has trapped) up to the throat so it can be swallowed and doesn’t reach the lungs.

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23
Q

What is the use of a lens in a microscope?

A

Magnify images.

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24
Q

What is the resolution of a microscope?

A

How well a microscope distinguishes between two points that are close together.

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25
Q

What does a higher resolution mean?

A

An image can be seen in more detail and more clearly.

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26
Q

How do light microscopes work?

A

They work by passing light through the specimen. They let us see things like nuclei and chloroplasts and we can use them to study living cells.

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27
Q

How do electron microscopes work?

A

They use electron rather then light and have a higher resolution and magnification than light microscopes. Therefore they let us view much smaller things in more detail like the internal structure of mitochondria and chloroplasts. However they can’t be used to view living cells.

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28
Q

What is the formula to work out total magnification?

A

Total magnification = Eyepiece lens magnification X Objective lens magnification.

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29
Q

What is the formula to work out magnification?

A

Magnification = Image size ÷ Real size

30
Q

What are enzymes and what do they do?

A

Living things produce enzymes which act as biological catalysts. Enzymes reduce the need for high temperatures and we only have enzymes to speed up the useful chemical reactions in the body.

31
Q

What is the substrate?

A

The molecule changed in the reaction.

32
Q

What is the active site?

A

Every enzyme has one and its the part that joins to the substrate to catalyse the reaction.

33
Q

What is required for an enzyme to work?

A

The substrate has to fit into the active site. If the substrates shape doesn’t match the active sites shape, then the reaction won’t be catalysed.

34
Q

How does and increase in temperature effect the rate of an enzyme-catalysed reaction and why?

A

Like with any reaction, a higher temperature increases the rate at first. But if it gets too hot, some of the bonds holding the enzyme together break. This changes the shape of the enzymes active site so the substrate won’t fit anymore.

35
Q

How does the pH of an enzyme being too high or low affect an enzyme?

A

If the pH is too high or too low, the pH interferes with the bonds holding the enzyme together. This changes the shape of the active site and denatures the enzyme.

36
Q

How does the substrate concentration affect the rate of reaction and why?

A

The higher the substrate concentration, the faster the reaction. This is because it’s more likely the enzyme will meet up and react with a substrate molecule. However, this is only true up to a certain point thought. After that, there are so many substrate molecules that the enzymes have about as much as they can cope with (all the active sites are full) so adding more makes no difference.

37
Q

What do digestive enzymes do?

A

Many of the molecules in the food we eat are too big to pass through the walls of our digestive system so digestive enzymes pass easily through the walls, soluble molecules.

38
Q

What do carbohydrases do?

A

They are enzymes that break down carbohydrates into simple sugars.

39
Q

Name an example of a carbohydrase?

A

Amylase.

40
Q

What do proteases do?

A

Converts proteins into amino acids.

41
Q

What do lipases do?

A

Convert lipids into glycerol and fatty acids.

42
Q

What is glycogen synthase?

A

An enzyme that joins together lots of chains of glucose molecules to make glycogen.

43
Q

What is glycogen?

A

A molecule used to store energy in animals.

44
Q

How are proteins made?

A

By joining amino acids together.

45
Q

What are biological molecules?

A

Molecules found in living molecules.

46
Q

How do you test the presence of starch using iodine?

A

Just add iodine to the test sample

1) If starch is present, the sample changes from browny-orange to a dark, blue-black colour.
2) If there’s no starch, it stays browny-orange.

47
Q

How do you use the emulsion test for testing the presence of lipids?

A

To find out if there aren any lipids in a sample:

1) Shake the test substance with ethanol for about a minute until it dissolves, then pour the solution in the water.
2) If there are any lipids present, they will precipitate out of the liquid to show up as a milky emulsion.
3) The more lipid there is, the more noticeable the milky colour.

48
Q

How do you use the biuret test for testing the presence of proteins?

A

1) First add a few drops of potassium hydroxide solution to make the solution alkaline.
2) Then add some copper (II) sulphate solution (which is bright blue)
- If there is no protein, the solution will stay blue.
- If protein is present, the solution will turn purple.

49
Q

How do you calculate the amount of energy in food?

A

Energy in food (in J) Mass of water (in g) X Temperature change of water (in ℃) X 4.2
Then work out how many joules are in each gram:
Energy per gram of food (in J/g) = Energy in food (in J) ÷ Mass of food (in g).

50
Q

What is diffusion?

A

The net movement of particles from an area of higher concentration to an area of lower concentration.

51
Q

What types of particles does diffusion happen with and why?

A

Liquids and gases because they are free to move about randomly.

52
Q

What is osmosis?

A

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

53
Q

What is a partially permeable membrane?

A

A membrane with very small holes in it. Only tiny molecules like water can fit through.

54
Q

What is active transport?

A

The movement of particles across a membrane against a concentration gradient (i.e. from an area of lower to an art of higher concentration) using energy transferred during respiration.

55
Q

Where is lipase made?

A

Pancreas and small intestine

56
Q

Where does lipase work?

A

Small intestine

57
Q

Where is protease made?

A

Stomach, pancreas and small intestine

58
Q

Where does protease work?

A

Stomach and small intestine

59
Q

Where is amylase made?

A

Salivary glands, pancreas and small intestine

60
Q

Where does amylase work?

A

Mouth and small intestine

61
Q

What is calorimetry?

A

Testing how much the temperature of water changes when we heat it with a known mass of a fuel.

62
Q

What is the function of the muscle cell?

A

Contracts to allow movement of body parts

63
Q

How is a muscle cell adapted to its function?

A

Contains long protein filaments that can slide past each other to shorten the cell. They contain many mitochondria to provide energy

64
Q

What is the function of the nerve cell?

A

It transmits electrical impulses from one part of the body to another

65
Q

How is the nerve cell adapted to its function?

A

Contains membrane proteins that carry out active transport of sodium and potassium ions to help “recharge” the cells

66
Q

What is the function of the blood cell?

A

Carry oxygen to body tissues that require it

67
Q

How is the blood cell adapted to its function?

A

Contains the protein haemoglobin, which binds to oxygen. It has no nucleus so there is more space available to carry oxygen

68
Q

How does microvilli help cells in the intestine adapt to their function?

A

It gives the cell a larger surface area which leads to increased absorption of water

69
Q

What does isotonic mean?

A

When particles spread out through the random movement of particles

70
Q

What does hypertonic mean?

A

A solutions at a higher concentration than the body or cell

71
Q

What does hypotonic mean?

A

A solutions at a lower concentration than the body of cell

GCSE Biology (9 decks)

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