Key Concepts In Biology

Question 1

What is a eukaryote?

Answer 1

Cells with a nucleus

Eg animal and plant cells

Question 2

What is a prokaryote?

Answer 2

A cell with no nucleus

Eg bacterial cells

Question 3

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

Answer 3

Vacuole
Chloroplast
Cell wall

Question 4

What is the job of the nucleus?

Answer 4

Controls what happens in the cell and carries genetic info

Question 5

What is the job of the cell membrane?

Answer 5

Controls what gets in and out

Question 6

What is the role of the cytoplasm?

Answer 6

Jelly like substance where chemical reactions happen

Question 7

What happens in ribosomes?

Answer 7

Proteins are made

Question 8

What happens in mitochondria

Answer 8

Aerobic respiration

Question 9

What happens in the vacuole?

Answer 9

Where cell sap is stored

Question 10

What do chloroplasts do?

Answer 10

Photosynthesis occurs

Question 11

What does the cell wall do?

Answer 11

Gives structure and support

Question 12

What is a specialised cell?

Answer 12

A cell which is adapted to perform a specific function

Question 13

What does the acrosome in a sperm cell do?

Answer 13

Breaks down the eggs jelly coat

Question 14

What type of nucleus does a sperm cell have?

Answer 14

Haploid

Question 15

What type of nucleus does an egg cell have?

Answer 15

Haploid

Question 16

What happens to the cell membrane after fertilisation?

Answer 16

It closes to stop more sperm entering

Question 17

What do cilia do?

Answer 17

They beat to and fro to move the egg towards the sperm

Question 18

Where are cilia also found?

Answer 18

In the airways to move mucus away from the lungs

Question 19

What does the chromosomal dna in a bacterial cell do?

Answer 19

Controls the cells activities

Question 20

What is plasmid dna?

Answer 20

Small loops of extr dna in a bacterial cell

Question 21

What is resolution?

Answer 21

The smallest distance between two points that can be seen as two points

Question 22

What does better resolution mean?

Answer 22

More detail

Question 23

What is the magnification equation?

Answer 23

Image size = actual size X magnification

Question 24

What are the 4 units used in microscopy?

Answer 24

Millimetres
Micrometres
Nanometres
Picometres

Question 25

What is an enzyme?

Answer 25

A protein that acts as a biological catalyst - speeds up chemical reactions

Question 26

What are they molecules that enzymes work on called?

Answer 26

Substrates

Question 27

Why are enzymes specific?

Answer 27

They only work with one specific substrate

Question 28

How do enzymes speed up reactions?

Answer 28

The substrate binds to the active site of the enzyme, then the enzyme breaks down the substrate making 2 products

Question 29

Types of enzymes Carbohydrates are... ... enzymes break down carbs in our food

Answer 29

Carbohydrates are large molecules made out of lots of sugar molecules joined together Carbohydrase enzymes

Question 30

Types of enzymes Proteins are... ... enzymes break down proteins in our food

Answer 30

Proteins are large molecules made out of lots of amino acids joined together Protease enzymes

Question 31

Types of enzymes Lipids are... ...enzymes break down the fats in our food

Answer 31

Lipids are large molecules made out of lots of glycerol and fatty acids joined together Lipase enzymes

Question 32

What is the equation for rate of reaction?

Answer 32

Amount of product formed/time

Question 33

If the temperature of enzymes is below the optimum, what happens?

Answer 33

There is more kinetic energy so the rate increases

Question 34

If the temperature of an enzyme is above the optimum what happens?

Answer 34

The bonds in the enzyme break and the shape of the active site changes so much that the enzyme denatures

Question 35

What happens when you change the pH of an enzyme a little?

Answer 35

Changes the shape of the active site, making the rate of reaction decrease, eventually denaturing

Question 36

Describe substrate concentration

Answer 36

As the rate of concentration of substrate increases, the rate of reaction increases but only up to a point After this, the rate plateaus (stays the same) There are more substrates than enzymes

Question 37

What is diffusion?

Answer 37

Passive movement of molecules from a high to low concentration

Question 38

What is osmosis?

Answer 38

The passive movement of water molecules from a high to low concentration across a partially permeable membrane

Question 39

What is active transport?

Answer 39

Movement of molecules from low to high concentration using energy from respiration so transport proteins can carry the molecules across the membrane

Question 40

How do you investigate osmosis?

Answer 40

Tubes with different concentration of substrates in them Equal sized piece of potato in each Measure weight of potato before and after putting it in