Nature And Variety Of Organisms

Question 1

What are the characteristics of living organisms?

Answer 1

• they need nutrition
• they respire
• they excrete their waste
• they move
• they can control their internal conditions
• they reproduce
• they can grow and develop

Question 2

What is a nucleus?

Answer 2

An organelle that contain genetic material that controls the cells activities.

Question 3

What is a cell membrane?

Answer 3

Controls what goes in and out of the cell

Question 4

What are mitochondria?

Answer 4

Small organelles where most of the reactions for aerobic respiration take place

Question 5

What are ribosomes?

Answer 5

Small organelles where protein is made in a cell

Question 6

What is cytoplasm?

Answer 6

A gel-like substance where most of the cells chemical reactions happen. It contains enzymes which control these reactions.

Question 7

What is a vacuole?

Answer 7

A large organelle that contains cell sap ( a weak solution of sugars and salts). Helps support the cell

Question 8

What is a cell wall?

Answer 8

A structure made of cellulose, which surrounds the cells membrane. It supports and strengthens the cell

Question 9

What are chloroplasts?

Answer 9

Where photosynthesis occurs, which makes food for the plant. Chloroplasts contains a green substance called chlorophyll which is used in photosynthesis.

Question 10

What is cell differentiation?

Answer 10

Is the process by which cell changes to become specialised for it’d job. As the cells change they develop different organelles that turn into different types of cells. This allows them to carry out specific functions.

Question 11

What are undifferentiated cells called?

Answer 11

Stem cells

Question 12

Where are stem cells found?

Answer 12

I’m early human embryos and bone marrow

Question 13

What are the risks of using stem cells in medicine?

Answer 13

Stem cells grown in a lab may become contaminated and pass it onto the patient making them sicker.

Question 14

Why are some people against stem cell research?

Answer 14

• feel that human embryos shouldn’t be used for experiments since each one is potential human life
• feel that scientists should be trying to find other sources of stem cells so people could be helped without embryos

Question 15

What type of organism are plant,animals and fungi?

Answer 15

Eukaryotic

Question 16

Features of plants:

Answer 16

-multicellular
-have chloroplasts, which mean they can photosynthesise
-their cells have cell walls which are made of cellulose
-plants store carbohydrates as sucrose or starch
E.g. flowering plants like : cereals (e.g maize), herbaceous legumes (e.g peas and beans)

Question 17

Features of animals:

Answer 17

-multicellular
-most have some kind of nervous coordination. This means they can responds rapidly to the changes in their environment
-can usually move around from one place to another
-often store carbohydrates in the form of glycogen
E.g. mammals (e.g human), insects (e.g houseflies and mosquitoes)

Question 18

Features of fungi:

Answer 18

-some are single celled
-others have a body called mycelium, which is made up of hyphae (thread like structures)
-can’t photosynthesise
-most feed my saprophytic nutrition
-store carbohydrate as glycogen
E.g. yeast, mucor

Question 19

What is saprophytic nutrition?

Answer 19

They secrete extracellular enzymes into the area outside their body to dissolve their food so they can then absorb nutrients

Question 20

Protoctists

Answer 20

-single celled & microscopic
-some have chloroplasts
E.g.chlorella (plant cell like), amoeba (animal cell like)-lives in pond water

Question 21

Bacteria

Answer 21

-single celled & microscopic
-don’t have a nucleus
-have a circular chromosome of DNA
-some can photosynthesise
-most bacteria feed of other organisms (living & dead)
E.g. lactobacillus bulgaricus, pneumococcus

Question 22

Viruses

Answer 22

• particles rather than cells
• reproduce in living cells
• infect all types of living organisms
• come in different shapes & sizes
• don’t have a cellular structure- they have a protein coat around some genetic material

Question 23

What is a catalyst?

Answer 23

A substance which increases the speed of a reaction, without busing changed or used up in the reaction

Question 24

What are metabolic reactions?

Answer 24

Enzymes speeding up useful chemical reactions in the body