B2 - Cells

Question 1

What are all living organisms made up of? [1]

Answer 1

Cells

Question 2

What are multicellular organisms? [1]

Answer 2

• Organisms that are made up of many millions of cells

Question 3

What is a unicellular organism?
Give an example. [1]

Answer 3

• Organisms made up of just a single cell.
• Bacteria

Question 4

What is cytoplasm? [3]

Answer 4

• Jelly-like substance containing water and dissolved substances like sugar and salts.
• Site of chemical reactions
• Contains organelles (cell parts)

Question 5

What is a cell membrane? [3]

Answer 5

• A partially permeable (selective) barrier
• Controls what goes in and out of the cell
• Contains receptor molecules

Question 6

What are ribosomes? [2]

Answer 6

• Tiny structures in the cytoplasm
• Proteins are made here
  (only visible with ELECTRON microscope)

Question 7

What are mitochondria? [3]

Answer 7

• Where respiration happens
• contains enzymes for respiration
• (only visible with ELECTRON microscope)

Question 8

What is a cell wall? [3]

Answer 8

• Surrounds the cell
• Made of tough fibre called cellulose
• Makes the wall rigid and supports the cell

Question 9

What is a nucleus? [3]

Answer 9

• Controls the activities of the cell
• Contains DNA
• Contains instructions to make new cells or new organisms

Question 10

What is a chloroplast? [3]

Answer 10

• Contains green chlorophyll
• Photosynthesis happens here
• Only found in green parts of the plant

Question 11

What is a vacuole? [2]

Answer 11

• Full of cell sap (watery solution of sugar and salts)
• Helps keep the cell rigid which supports the plant and keeps it upright.

Question 12

What do plant cells have that animal cells don’t? [3]

Answer 12

1. Chloroplasts
2. Vacuole
3. Cell wall

Question 13

What do bacteria cells not have? [3]

Answer 13

1. Nucleus
2. Mitochondria
3. Chloroplasts

Question 14

The cell wall in a bacteria cell is made of what? [1]

Answer 14

Peptidoglycan, not cellulose

Question 15

What do plasmids do? [1]

Answer 15

Provide extra genes

Question 16

The DNA in bacteria cells are in what shape? [1]

Answer 16

• Double Helix
• Circular

Question 17

Describe the function and structure of a red blood cell. [4]

Answer 17

• Transports oxygen
• Cytoplasm contains haemoglobin - a protein which carries oxygen molecules
• NO nucleus = more space for haemoglobin
• Bi-concave disc shape which increases surface area = more absorption of oxygen

Question 18

Describe the function and structure of a ciliated cell. [3]

Answer 18

• Movement of mucus in the trachea and bronchi
• Hair-like structures called CILIA
• Cilia move mucus and trap the particles to the throat

Question 19

Describe the function and structure of a palisade mesophyll cell. [3]

Answer 19

• Photosynthesis
• Lots of chloroplasts for maximum photosynthesis
• Column shaped to maximise sunlight absorption

Question 20

Describe the function and structure of a root hair cell. [3]

Answer 20

• Absorption of water and minerals
• Thin walls for quick water movement
• Root hair increases surface area for maximum water and minerals ions

Question 21

Describe the function and structure of a sperm cell. [4]

Answer 21

• Reproduction
• Haploid nucleus contains genetic material for fertilisation
• FLAGELLUM (tail) enables swimming for sperm
• Middle part = acrosome contains digestive enzymes so penentration can happen

Question 22

Describe the function and structure of an egg cell. [5]

Answer 22

• Reproduction
• Cytoplasm contains nutrients for early embryo growth
• Cell membrane changes after fertilisation by a single sperm so that no more can enter
• Jelly coat stops other cells from coming in
• Haploid nucleus contains genetic material for fertilisation

Question 23

What does HAPLOID nucleus mean?

Answer 23

A nucleus that contains half the normal number of chromosomes.

Question 24

Describe the function and structure of a neurone cell. [5]

Answer 24

• Conduction of nerve impulses
• Long so that nerves can run to and from different parts of the body to central nervous system
• Extensions and branches for communication with cells, muscles, glands
• AXON = extension of cytoplasm away from the cell body
• FATTY SHEATH = which insulates the nerve cell and speeds up nerve impulse

Question 25

What is a 'tissue'? [1]

Answer 25

A group of similar cells working together

Question 26

What is an 'organ'? [1]

Answer 26

A group of tissues working together to do a job

Question 27

What is an 'organ system'? [1]

Answer 27

A group of organs working together to do a job

Question 28

What is an 'organism'? [1]

Answer 28

A group of organ systems working together to do a job

Question 29

How do you work out the total magnification? [2]

Answer 29

magnification of EYEPIECE LENS x magnification of OBJECTIVE LENS

Question 30

How do you work out the magnification of an image? [2]

Answer 30

I -------- A | M Image size = I Actual size = A Magnification = M I = A x M A = I / M M = I / A

Question 31

To go from millimetres to micrometres, what do you do? [1]

Answer 31

x 1000

Question 32

To go from micrometres to millimetres, what do you do? [1]

Answer 32

/ 1000