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Flashcards in Key Concepts Deck (67):
1

What are eukaryotes?

Complex: animal and plant cells

2

What are prokaryotes?

Small & simple: bacteria

3

Nucleus

Contains genetic material
Controls the activities of the cell
Genetic material arranged into chromosomes

4

Cytoplasm

Gel-like substance
Chemical reactions happen
Contains enzymes

5

Cell membrane

Holds the cell together
Controls what goes in and out

6

Mitochondria

Where most of the reactions for respiration happen
Powerhouse of the cell

7

Ribosomes

Involved in translation of genetic material in protein synthesis

8

Cell wall

Made of cellulose
Supports cell and strengthens it
(Plants)

9

Large vacuole

Contains cell sap
Weak solution of sugar and salts
Internal pressure to support cell
(Plants)

10

Chloroplasts

Where photosynthesis occurs
Makes bait for the plant
Contain chlorophyll
(Plants)

11

Chromosomal DNA

Controls cells activities & replication
Floats free in cytoplasm
(Bacterial)

12

Plasmid DNA

Small loops of extra DNA
Genes for drug resistance
(Bacterial)

13

Flagellum

Long hair like structure
Rotated to make bacterium move
Move bacteria away from harmful substances

14

What are the 2 cells used in sexual reproduction?

Egg cell
Sperm cell

15

What’s the main function of the egg cell?

Carry the females DNA and to nourish the developing embryo in early stages

16

Why is there nutrient in the cytoplasm of an egg cell?

To feed the embryo

17

What is a haploid cell?

A cell that only contains half the number of chromosomes of a normal cell

18

What happens in the egg cell straight after fertilisation?

It’s membrane changes structure to stop any more sperm getting in.
Therefore the offspring gets the right amount of DNA

19

What is the function of the sperm cell?

Transport the males DNA to the females egg

20

Why does a sperm cell have a long tail?

So it can swim to the egg

21

Why does a sperm cell have a lot of mitochondria in the middle section?

To provide the energy needed to swim this distance

22

What is an acrosome?

The front of the head of a sperm cell where it stores enzymes to digest it’s way through the membrane of the egg cell

23

Where are epithelial cells found?

Lining the surfaces of organs

24

What is cilia

Hair like structures

25

What do epithelial cells do?

Move substances in one direction along the surface of the tissue

26

How do you work out magnification

Image size ➗ real size

27

How do you calculate total magnification?

Eyepiece lens magnification x objective lens magnification

28

What are enzymes?

Catalysts produced by living things

29

What is a catalyst?

A substance which increases the speed of a reaction without being changed or used up in the reaction.

30

What type of catalyst is an enzymes found in living things?

Biological catalysts

31

Why do enzymes have special shapes

So they can catalyse reactions

32

What do chemical reactions usually involve?

Being split apart or joined together

33

What is a substrate

The molecule changed in a reaction

34

What is an active site?

The prt where the enzyme joins on to its substrate to catalyse the reaction

35

What is the lock and key mechanism?

The substrate must fit into the active site and if it doesn't, the reaction won't be catalysed. If it fits I'm looks like how a key fits into a lock.

36

What can affect the rate of reaction for enzymes

Temperature
pH
Substrate concentration

37

What happens when an enzyme becomes denatured?

The enzyme has become too hot/ too high/low pH
The bonds holding the enzyme together have broken
The active site of the enzyme has changed
Substrate no longer fits

38

What is an optimum temperature/pH

What temperature/pH the enzyme works best at

39

What happens if there is a high substrate concentration?

The reaction will be faster

40

How do you calculate the rate if reaction

1000/time

41

Why is it important organisms can break down big molecules?

So they can be used for growth and other life processes

42

What do plants store energy in the form of?

Starch

43

What happens when plants need energy?

Enzymes break down starch into smaller molecules (sugar)

44

Carbohydrases covert

Carbohydrates into simple sugars
Starch *amylase* ➡️ maltose and other sugars

45

Protease convert

Proteins into amino acids
Proteins *protease enzymes* ➡️ amino acids

46

Lipases convert

Lipids into glycerol and fatty acids
Lipid *lipase enzymes* ➡️ glycerol and fatty acids

47

How are carbohydrates synthesised

By joining together simple sugars

48

How are proteins made

By joining amino acids together

49

How do you test for sugars

Using Benedict's Reagent

50

If there's sugar what colour will Benedict's reagent turn to

Blue ➡️ Red

51

What is used to test for starch

Iodine solution

52

What happens to iodine solution if starch is present

It changes from browny orange to dark blue-black colour

53

What is the test for lipids

The emulsion test

54

What is the substance used to test for lipids

Ethanol

55

What happens if lipids are present when mixed with ethanol?

The liquid will go milky when shook

56

What is the proteins test?

The biuret test

57

What do you add to the substance to test for proteins

Potassium hydroxide
Copper surface

58

What colour will the solution turn in the biuret test if protein is present

Blue ➡️ purple

59

How do you test to see how much energy bait contains?

Burn it (calorimetry)

60

How do you calculate energy in food?

Mass of water x temperature change in water x 4.2

61

How do you work out how much energy per grams of food there is

Energy in food/ mass of food

62

What is diffusion

The movement of particles from an area of high concentration to low concentration

63

What size molecules can be diffused through cell membranes

Small

64

What is osmosis

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

65

What is a partially permeable membrane

A membrane with small holes

66

What is active transport

The movement of particles across a membrane against a concentration gradient using energy transferred during respiration.

67

How do you investigate osmosis

By putting potato cylinders into different concentrations of sucrose solution to see what effect different water concentrations have on them