CB1 /

Question 1

Eukaryotes

Answer 1

Eukaryote cells are complex and found in plants, animals, fungi and protists
• Nucleus
• Membrane enclosed organelle
• Chromosomes in pairs
• Streaming in the cytoplasm

Question 2

Prokaryotes

Answer 2

• Prokaryotes cells are smaller and simpler (e.g. bacteria)
• A prokaryote is an organism made up of prokaryotic cells
• It’s a single-celled organism
• Single DNA loop
• No nucleus
• No membrane enclosed organelles
• Single chromosome
• Plasmids - can replicate and move between cells so that genetic information can be shared

Question 3

Function: Nucleus

Plant and Animal cell

Answer 3

Contains genetic material that controls the activities of the cell

Question 4

Function: Cytoplasm

Plant and Animal cell

Answer 4

• Gel-like substance where most of the chemical reactions take place
• It controls enzymes that control these chemical reactions

Question 5

Function: Cell membrane

Plant and Animal cell

Answer 5

Holds the cell together and controls what goes in and out

Question 6

Function: Mitochondria

Plant and Animal cell

Answer 6

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

Question 7

Function: Ribosomes

Plant and Animal cell

Answer 7

Ribosomes are responsible for synthesising (making) proteins

Question 8

Function: Cell wall

Plant cell

Answer 8

It supports and protects the cell

Question 9

Function: Vacuole

Plant cell

Answer 9

• Contains cell sap, a weak solution of sugar and salts

* It maintains the internal pressure to support the cell

Question 10

Function: Chloroplasts

Plant cell

Answer 10

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

Question 11

Function: Chromosomal DNA

Bacterial cell

Answer 11

Controls the cell’s activities and replication. It floats free in the cytoplasm.

Question 12

Function: Plasmid DNA

Bacterial Cell

Answer 12

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.

Question 13

Function: Flagellum

Bacterial cell

Answer 13

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

Question 14

Resolution

Answer 14

Resolution is the ability to distinguish between two or more objects that are close together

Question 15

Microscopes

Answer 15

Microscopes uses lenses to magnify images

Question 16

Parts of a microscope

Answer 16

• Eyepiece lens
• Objective lenses
• Stage
• Light
• Fine focus
• Focussing wheel

Question 17

Magnification

Answer 17

Magnification tells us how many times larger an image is seen through a microscope compared to the real object

Question 18

Formulae: magnification

Answer 18

Magnification = image size ÷ real size

Question 19

Enzymes

Answer 19

Enzymes are catalysts produced by living things
• For the enzyme to work, the substrate has to fit in to the active site. This is called the ‘lock and key‘ mechanism because the substrate fits in to the enzyme just like a key fits in to a lock.

Question 20

Catalyst

Answer 20

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

Question 21

Enzymes breakdown…

Answer 21

Enzymes break down big molecules

• Proteins, lipids and some carbohydrates are big molecules

Question 22

Carbohydrases

Answer 22

Enzymes called carbohydrases convert carbohydrates in to simple sugars. E.g. amylase. It breaks down starch

Question 23

Proteases

Answer 23

Proteases convert proteins in to amino acids

Question 24

Lipases

Answer 24

Lipases convert lipids in to glycerol and fatty acids