The Nature and Variety of Organisms

Question 1

What are the characteristics of living organisms?

Answer 1

Movement
Respiration
Sensitivity

Homeostasis

Growth
Reproduction
Excretion
Nutrition

Question 2

What are the levels of organisation in organisms?

Answer 2

Organelles (Parts of a cell)
Cells
Tissues
Organs
Organ systems
Organism

Question 3

What organelles are found in both animal and plant cells?

Answer 3

Nucleus
Cytoplasm
Mitochondria
Ribosomes
Cell membranes

Question 4

What organelles are found only in plant cells?

Answer 4

Cell walls
Large vacuoles
Chloroplasts

Question 5

What function does the nucleus provide?

Answer 5

Contains the cell’s genetic material and controls the cell’s activities

Question 6

What does the cell membrane do?

Answer 6

Outer layer of the cell. It allows substances in and out of the cell

Question 7

What does the cytoplasm do?

Answer 7

Cell’s chemical reactions happen here. It’s a gel-like substance

It contains enzymes which control these reactions

Question 8

What do the mitochondria do?

Answer 8

Where aerobic respiration takes place

Question 9

What do the ribosomes do?

Answer 9

Proteins are made here through protein synthesis

Question 10

What do chloroplasts do?

Answer 10

Photosynthesis happens here. They contain green substances called chlorophyll

Question 11

What is the cell wall?

Answer 11

A rigid structure made of cellulose which surrounds the cell membrane. It supports the cell and strengthens it

Question 12

What is a large vacuole?

Answer 12

Supports the cell. Contains cell sap to do this

Question 13

What is cell differentiation?

Answer 13

The process by which a cell changes to become specialised for a specific job

Question 14

Why are embryonic stem cells special?

Answer 14

They have the potential to turn into any kind of cell

Question 15

Do adults have stem cells?

Answer 15

Yes, but they’re only found in certain places, e.g. the bone marrow.
They can only turn into specific cells, like RBC

RBC = Red blood cells

Question 16

How can adult stem cells be used to cure diseases?

Answer 16

Stem cells transferred from bone marrow of a healthy person can replace faulty blood cells in a sick patient

Question 17

How can embryonic stem cells be used to cure disease?

Answer 17

Can replace faulty cells. They can also make insulin-producing cells (for those with diabetes) or nerve cells (those who are paralysed)

Question 18

Why are some people against stem cell research?

Answer 18

Some see embryos as potential human lives, and therefore shouldn’t be used for experiments

Question 19

What are the main features of plants?

Answer 19

Eukaryotic

Have chloroplasts, therefore photosynthesise

Store carbohydrates as sucrose or starch

Question 20

What are the main features of animals?

Answer 20

Eukaryotic

Have nervous coordination so can rapidly respond to changes in an environment e.g. can move

Store carbohydrates as glycogen

Question 21

What are the main features of fungi?

Answer 21

Most are eukaryotic

Have a body called mycelium made up of hyphae

Cell walls made of chitin

Store carbohydrates as glycogen

Question 22

How do plants feed?

Answer 22

Autotrophicly

Question 23

How do animals feed?

Answer 23

Heterotrophically

Question 24

How do fungi feed?

Answer 24

Saprotrophically -> Secrete extracellular enzymes into the area outside their body and dissolve the food

Question 25

What are some examples of fungi?

Answer 25

Yeast (single-celled)
Mucor

Question 26

What are the characteristics of protoctists?

Answer 26

Mostly single-celled
Some more like plant cells, others are more similar to animal cells

Question 27

What are some examples of protoctists?

Answer 27

Chlorella
Amoeba
Plasmodium (causes malaria)

Question 28

What are the characteristics of bacteria?

Answer 28

Prokaryotes

Don’t have a nucleus, instead they have circular chromosomes of DNA

Both heterotrophic and saprotrophic

Question 29

What are some examples of bacteria?

Answer 29

Lactobacillus bulgaricus (used to make yoghurt)
Pneumococcus (causes pneumonia)

Question 30

What are the characteristics of viruses?

Answer 30

NOT LIVING

Can only reproduce inside living cells. It is a parasite

Infect all types of organisms

Do not have a cellular structure -> they have a protein coat around some genetic material

Parasite = Depends on another organism to survive

Question 31

What are some examples of viruses?

Answer 31

HIV
Influenza virus
COVID-19
Tobacco Mosaic Virus (Discolours leaves and prevents them from producing chloroplasts)

Question 32

What are pathogens?

Answer 32

Organisms that cause disease.
Include some fungi, protoctists, bacteria and viruses (even though not technically living)

Question 33

What is a catalyst?

Answer 33

A substance that speeds up the rate of reaction without being changed or used up

Question 34

What does ‘optimum temperature/pH’ mean?

Answer 34

The temperature/pH that that enzyme works best at.
Below the optimum and the reaction is slow. Above the optimum and the enzyme denatures

Question 35

What is diffusion?

Answer 35

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

Passive process -> Doesn’t require energy

Question 36

What is osmosis?

Answer 36

The net movement of water molecules from an area of high concentration to an area of low concentration through a semi-permeable membrane

Question 37

What is active transport?

Answer 37

The movement of particles against the concentration gradient, from an area of low concentration to an area of high concentration. It requires energy released from respiration

Question 38

Which 4 factors affect the movement of a substance?

Answer 38

1. Surface Area to Volume ratio
2. Distance that the substance needs to travel
3. Temperature
4. Concentration gradient