Biology - Topic 1 - Key Concepts in Biology Flashcards Preview

GCSE Science Edexcel Combined > Biology - Topic 1 - Key Concepts in Biology > Flashcards

Flashcards in Biology - Topic 1 - Key Concepts in Biology Deck (70):
1

What does a microscope do?

makes small objects appear larger/magnifies small objects

2

What part of a microscope do you look through? 

eyepiece lens

3

Which part of a microscope do you use to get a clear image?

the focusing wheel

4

Put these in order of size, biggest first: atom, animal cell, cell nucleus, muscle tissue, protein molecule, water molecule 

muscle tissue, animal cell, cell nucleus, protein molecule, water molecule, atom 

5

A microscope has a ×5 eyepiece lens and a ×5 objective lens. What is the total magnification?

×25; 5 × 5 = 25

6

A human hair has a width of 100 µm but appears 20 mm wide in a photo. What magnification is the photo? 

×200; 20 mm = 20 000 µm; 20 000 ÷ 100 = 200

7

How many millimetres are there in a metre? 

1000

8

What unit is 1000 times smaller than a millimetre?

micrometre, µm

9

What is the unit symbol for a nanometre?

nm

10

Name one part you could find in a plant cell but not an animal cell.

cell wall, chloroplasts, permanent vacuole

11

What process happens in a mitochondrion?

aerobic respiration

12

What is one function of a plant cell’s permanent vacuole?

to help keep the cell rigid/to store substances

13

In which part of a plant cell is cell sap stored?

vacuole

14

In which part of a cell would you find chromosomes?

nucleus

15

When you look down a microscope, what is the area that you see called?

field of view

16

Why can an electron microscope detect smaller structures in cells than a light microscope?

it has better magnification and better resolution

17

What is a picture taken with a microscope called?

micrograph

18

Some microscope pictures have a small line drawn on them with information about how long the line is when unmagnified. What is this line called?

scale bar

19

List three sub-cellular structures that are usuallyfound in animal cells.

cell membrane, nucleus, mitochondria, ribosomes

20

Which cell structure controls what enters and leaves the cell?

cell membrane

21

Which cell structure controls how the cell works?

nucleus

22

Which plant cell structure contains chlorophyll?

chloroplast

23

What is the function of the cell structure that contains chlorophyll?

to capture energy from light for photosynthesis/to produce glucose using photosynthesis

24

Describe the function of the cell wall

supports and protects the cell

25

What is the function of ribosomes?

manufacture of proteins

26

What are gametes?

sex cells

27

A bacterium is 20 µm long. How long is it in metres?

0.00002 m

28

A bacterium is 5 µm wide. How wide is it in nanometres?

500nm

29

What do bacteria use to move themselves?

flagella

30

Animal and plant cells are eukaryotic. What word describes bacterial cells?

prokaryotic

31

Name one structure that an animal cell would have but a bacterial cell would not.

nucleus, mitochondria

32

What is 1 × 10^6m written as an ordinary number?

1 000 000 m

33

Name two substances that might be found in the cytoplasm of an egg cell to provide energy.

carbohydrate or starch, lipid or fat or oil

34

In which system of the body is food broken down?

digestive system

35

Why do we need to break food down?

because the molecules in food are too large to cross cell membranes

36

In which organ of the body is digested food absorbed?

small intestine

37

Which group of molecules help to digest food?

enzymes

38

Name an example of an enzyme

amylase, protease, lipase

39

What does a sperm cell use enzymes for?

to digest a path through the jelly coat of the egg cell

40

Do plants contain enzymes?

yes – they control many reactions inside plant cells

41

Name a part of a plant where you might findenzymes.

anywhere a reaction takes place, e.g. in chloroplasts for photosynthesis, in mitochondria for respiration, where starch grains are made

42

What nutrient is starch an example of?

carbohydrate

43

Why are proteins and carbohydrates examples of polymers?

They are made up of many similar molecules/monomers.

44

Which monomers make up starch?

glucose

45

Which monomers make up a protein?

amino acids

46

Are enzymes carbohydrates, proteins or lipids?

proteins

47

Which group of substances are fats and oils examples of?

lipids

48

Name one food that contains a lot of starch.

potato, pasta, bread, rice

49

What effect does the enzyme amylase have on starch?

breaks it down to small sugars

50

Food provides nutrients for growth. What else is it a source of, which we need for activity?

energy

51

What are the subunits (small molecules) that make up carbohydrates?

simple sugars, e.g. glucose

52

Which two kinds of subunits form lipids (fats and oils)?

fatty acids and glycerol

53

Which subunits make up enzymes?

amino acids

54

Amylase is a kind of enzyme. Where is it found?

mouth/salivary glands and small intestine/pancreas

55

Why are enzymes called biological catalysts?

They are molecules found inside living organisms that speed up the rate of reactions.

56

What is a substrate?

A molecule that is changed in a reaction

57

What is the substrate for amylase?

starch

58

Starch synthase is an enzyme that catalyses the synthesis of starch. Explain what this means.

The enzyme combines with subunits/small sugar molecules and helps them join together to form starch.

59

Why do different enzymes have different 3D shapes?

The amino acids are arranged in a different order in different proteins.

60

Which kind of large organic molecule does a protease digest?

proteins

61

What is the name of the part of an enzyme into which the substrate fits?

active site

62

Why do most enzymes only work with onesubstrate?

Only substrates with the same shape as the active site can sit in the site and take part in the reaction.

63

Enzymes are specific to their substrate. What doesthis mean?

The enzyme will only work with particular substrates -those substrates that have the right shape.

64

Which term describes an enzyme in which the active site has permanently changed shape?

denatured

65

What effect does a large change of shape of an enzyme's active site have on how the enzyme works?

The enzyme no longer works.

66

Give two examples of changes in the cell environment that could cause the active site to change shape.

pH, temperature

67

Carbon dioxide is produced inside a cell and moves out of the cell by diffusion. What does this mean?

there is an overall movement of gas particles fromwhere there are more of them to where there are fewer

68

Name two substances that plants take in from the soil through their roots

water and dissolved mineral salts

69

There is a 5% sucrose solution and a 10% sucrose solution. Which solution has the higher concentration of sucrose?

10% solution

70

Two beakers contain the same volume of solution. One is a 10% sodium chloride solution, the other is a 5% sodium chloride solution. Which beaker contains more water molecules?

5% solution