b1 - cell structure and transport

Question 1

give four features of light microscopes

Answer 1

1) use a bean of light to form an image
2) can magnify objects up to 2000 times (school - 400 times)
3) used to view living objects
4) relatively cheap and easy to transport

Question 1

give four features of electron microscopes

Answer 1

1) use a beam of electrons to form an image
2) can magnify objects up to 2,000,000 times
3) cannot be used for living objects
4) expensive and need to be kept in special conditions

Question 2

give the two types of electron microscope

Answer 2

1) transmission electron microscope which gives 2D images
2) scanning electron microscope which gives 3D images but lower magnification

Question 3

define resolving power

Answer 3

ability to separate small close together dots/objects

Question 4

what is the resolving power of a light microscope?

Answer 4

200 nm

Question 5

what is the resolving power of a transmission electron microscope?

Answer 5

0.2 nm

Question 6

benefits of a transmission electron microscope over a light microscope?

Answer 6

• higher magnification
• better resolving power

Question 7

what is 1km equal to?

Answer 7

1000 m

Question 8

what is 1m equal to?

Answer 8

100 cm

Question 9

what is 1cm equal to?

Answer 9

10 mm

Question 10

what is 1 mm equal to?

Answer 10

1000 micrometres (um)

Question 11

what is 1 um equal to?

Answer 11

1000 nm

Question 12

give magnification formula

Answer 12

magnification = image size/object size

Question 13

define nucleus

Answer 13

• diameter 10 um
• controls cell activities

Question 14

define cytoplasm

Answer 14

• liquid gel in which the organelles are suspended
• where many chemical reactions take place

Question 15

define cell membrane

Answer 15

controls movement of substances such as glucose and mineral ions into the cell, and other substances such as urea and hormones out of the cell

Question 16

define mitochondria

Answer 16

where energy is transferred during aerobic respiration

Question 17

define ribosomes

Answer 17

where protein synthesis takes place

Question 18

define algae

Answer 18

simple aquatic organisms with features similar to plant cells

Question 19

what features do plants and algae additionally have?

Answer 19

• rigid cell wall made of cellulose for support
• chloroplasts containing chlorophyll for photosynthesis, chloroplasts absorb light to make food
• permanent vacuole containing cell sap keeping the cell rigid and helps to support the plant

Question 20

define eukaryotic

Answer 20

contains cell membran, cytoplasm and nucleus (nucleus contains chromosomes which are made of genetic material called DNA)

Question 21

define prokaryotic

Answer 21

single-celled living organisms

Question 22

give an example of a prokaryotic cell

Answer 22

• bacteria, cell membrane and cell wall surrounding cytoplasm not made of cellulose
• bacteria do not have a nucleus, genetic material is found in cytoplasm as a long circle of DNA
• some prokaryotic cells have plasmids
• some bacteria have a protective slime capsule, other have flagella for movement
• bacteria may cause stored food to decompose