B2.1 - Cell Structure

Question 1

what are all living organisms made of?

Answer 1

cells

Question 2

what are the structures of cells in BOTH: animal and plant cells?

Answer 2

cell membrane, nucleus, cytoplasm and mitochondria.

Question 3

what structure cannot be seen in a cells underneath a microscope?

Answer 3

mitochondria and ribosomes

Question 4

what are the structures of a PLANT CELL?

Answer 4

cell wall, cell membrane, nucleus, cytoplasm, vacuole, chloroplasts and mitochondria.

Question 5

what are the structures of an ANIMAL CELL?

Answer 5

cell membrane, nucleus, cytoplasm, mitochondria and ribosomes

Question 6

describe the function of a cell wall

Answer 6

• tough layer made of cellulose
• surrounds the cell membrane
• freely permeable so it allows water and salt to pass through
• protects and surrounds the cells as well as prevents the cell from bursting

Question 7

describe the function of a cell membrane

Answer 7

• inner layer which surrounds the cell

- partially permeable so it controls what substances enter or leave the cell

Question 8

describe the function of a nucleus

Answer 8

• contains DNA in the form of chromosomes

- controls cell division, cell development and cell activities

Question 9

describe the function of a cytoplasm

Answer 9

• it contains cell organelles
• chemical reactions take place here
• is jelly like and 70% water

Question 10

describe the function of a mitochondria

Answer 10

• found in the cytoplasm and are tiny organelles

- responsible for producing energy from food substances through the process of aerobic respiration

Question 11

describe the function of a vacuole

Answer 11

• it is a fluid filled space surrounded by a membrane
• it contains salts and sugars which is ‘ cell sap ‘
• it helps keep the plant turgid (firm)

Question 12

describe the function of chloroplasts

Answer 12

• organelle which contains chlorophyll

- chlorophyll traps light energy for photosynthesis

Question 13

describe the function of ribosomes

Answer 13

• produces, transports and stores proteins

- it looks like a group of flattened curves

Question 14

what are the different specialised cells?

Answer 14

red blood cells
root hair cells
egg cell
sperm cell
palisade mesophyll cell 
ciliated cells

Question 15

what is the structure and function of red blood cells?

Answer 15

structure:
- has no nucleus which gives extra space for oxygen
- has a biconcave shape which gives the cell a large surface area to volume ratio

function:
- transports oxygen around the body

Question 16

what is the structure and function of root hair cells?

Answer 16

structure:
- has long projections which increases the surface area of the cell
- absorbs water through the process of osmosis
- large surface area increases the rate of absorption

function:
- absorbs water and mineral ions from the soil through the process of osmosis

Question 17

what is the structure and function of palisade mesophyll cells?

Answer 17

structure:

• a type of plant cell
• have numerous chloroplasts

function:
- the numerous chloroplasts absorb light energy needed for photosynthesis.

Question 18

what is the structure and function of ciliated cells?

Answer 18

structure:

• have small projections called cilia
• they have hair like structures

function:
- the tiny hair-like structures on the surface of the cell are used to sweep mucus and other bacteria in the trachea and bronchi sweeping it away from the lungs to the back of the throat where it can be swallowed

Question 19

what is the structure and function of egg cells?

Answer 19

structure:
- they have a large amount of cytoplasm containing yolk droplets made up of fat and protein
- nucleus carries genetic information

function:
- house an embryo while it grows providing a lot of energy for growth from the large food store
- reproduction

Question 20

what is the structure and function of sperm cells?

Answer 20

structure:
- The head of the sperm is shaped like an oval and it contains the nucleus which carries the genetic information
- The tip of the sperm is called an ‘acrosome’ which secretes enzymes to digest the cells around an egg and the egg membrane.
- The midpiece is packed with mitochondria to provide energy for movement
- The tail uses a whip-like action which enables the sperm to swim.

function:
- Reproduction achieved by fertilising the egg.

Question 21

what is the equation for magnification?

Answer 21

MAGNIFICATION = MEASURED LENGTH (MM) / ACTUAL LENGTH (MM)