Topic 1: Key Concepts in Biology

Question 1

What is a eukaryotic cell?

Answer 1

A cell with a nucleus and membrane-bound organelles

Question 2

What is a prokaryotic cell?

Answer 2

A cell without a nucleus with DNA free in the cytoplasm

Question 3

What are the parts of an animal cell?

Answer 3

Nucleus cytoplasm cell membrane mitochondria ribosomes

Question 4

What are the parts of a plant cell?

Answer 4

Nucleus cytoplasm cell membrane mitochondria ribosomes chloroplasts permanent vacuole cell wall

Question 5

What are the parts of a bacterial cell?

Answer 5

Cytoplasm cell membrane cell wall plasmid DNA chromosomal DNA flagellum

Question 6

What is the function of the nucleus?

Answer 6

Contains DNA that controls the cell’s activities

Question 7

What is the function of mitochondria?

Answer 7

Site of aerobic respiration to release energy

Question 8

What is the function of ribosomes?

Answer 8

Site of protein synthesis

Question 9

What is the function of the cell membrane?

Answer 9

Controls what enters and leaves the cell

Question 10

What is the function of the cytoplasm?

Answer 10

Where chemical reactions take place

Question 11

What is the function of the permanent vacuole?

Answer 11

Contains cell sap to help support the cell

Question 12

What is the function of chloroplasts?

Answer 12

Site of photosynthesis and contains chlorophyll

Question 13

What is the function of the cell wall?

Answer 13

Made of cellulose and supports and protects the cell

Question 14

What is the function of plasmid DNA in bacteria?

Answer 14

Small loop of extra DNA which may contain useful genes

Question 15

What is the function of flagella in bacteria?

Answer 15

Helps the cell move

Question 16

What is cell differentiation?

Answer 16

The process by which a cell becomes specialised

Question 17

What is a stem cell?

Answer 17

An undifferentiated cell that can become many types of cells

Question 18

How is a sperm cell specialised?

Answer 18

It has a tail mitochondria acrosome and haploid nucleus

Question 19

What is the function of the acrosome?

Answer 19

Contains enzymes to digest the egg’s membrane

Question 20

How is an egg cell specialised?

Answer 20

It has nutrients in the cytoplasm a haploid nucleus and a membrane that changes after fertilisation

Question 21

How is a ciliated epithelial cell specialised?

Answer 21

It has cilia that beat to move substances like mucus

Question 22

What is a light microscope used for?

Answer 22

To view whole cells and large organelles with lower resolution

Question 23

What is an electron microscope used for?

Answer 23

To view smaller structures with higher resolution and magnification

Question 24

What is magnification?

Answer 24

How much larger the image is compared to the object

Question 25

What is resolution?

Answer 25

The ability to distinguish between two close objects

Question 26

What is the formula for magnification?

Answer 26

Magnification equals image size divided by actual size

Question 27

What is total magnification?

Answer 27

Total magnification equals eyepiece lens times objective lens

Question 28

How big is a millimetre in metres?

Answer 28

One millimetre is ten to the minus three metres

Question 29

How big is a micrometre in metres?

Answer 29

One micrometre is ten to the minus six metres

Question 30

How big is a nanometre in metres?

Answer 30

One nanometre is ten to the minus nine metres

Question 31

How big is a picometre in metres?

Answer 31

One picometre is ten to the minus twelve metres

Question 32

What is an enzyme?

Answer 32

A biological catalyst that speeds up reactions without being used up

Question 33

How do enzymes work?

Answer 33

The substrate fits the enzyme's active site like a key in a lock

Question 34

What happens if the active site changes shape?

Answer 34

The enzyme becomes denatured and cannot bind the substrate

Question 35

How does temperature affect enzyme activity?

Answer 35

Rate increases to optimum then drops as enzymes denature

Question 36

How does pH affect enzyme activity?

Answer 36

Each enzyme has an optimum pH and becomes denatured if too high or low

Question 37

How does substrate concentration affect enzyme activity?

Answer 37

Rate increases then levels off as active sites become saturated

Question 38

What is the optimum temperature for enzymes?

Answer 38

The temperature where the enzyme works fastest without denaturing

Question 39

What is the optimum pH for enzymes?

Answer 39

The pH where the enzyme is most active and stable

Question 40

What is a digestive enzyme?

Answer 40

An enzyme that breaks down large food molecules

Question 41

What do carbohydrases do?

Answer 41

They break down carbohydrates into simple sugars

Question 42

What do proteases do?

Answer 42

They break down proteins into amino acids

Question 43

What do lipases do?

Answer 43

They break down lipids into fatty acids and glycerol

Question 44

What is synthesis?

Answer 44

The building of larger molecules from smaller ones

Question 45

How do you test for starch?

Answer 45

Add iodine and look for blue black colour

Question 46

How do you test for reducing sugars?

Answer 46

Add Benedict’s and heat and look for red orange green colour

Question 47

How do you test for proteins?

Answer 47

Add Biuret solution and look for purple colour

Question 48

How do you test for lipids?

Answer 48

Add ethanol and water and look for white emulsion

Question 49

What is the formula for energy in food?

Answer 49

Energy equals mass of water times 4.2 times temperature rise