biology paper 1

Question 1

1. Where is the genetic material in a prokaryotic cell?

Answer 1

In a bacterial DNA loop and there may be one or more plasmid rings.

Question 2

2. Where is the genetic material in a eukaryotic cell?

Answer 2

The DNA is in chromosomes enclosed in a nucleus.

Question 3

4. Why do scientists use prefixes?

Answer 3

To make very small numbers more manageable

Question 4

Nucleus

Answer 4

Contains genetic material, which controls the activities of the
cell

Question 5

Cytoplasm

Answer 5

Most chemical processes take place here, controlled by

enzymes

Question 6

Cell membrane

Answer 6

Controls the movement of substances into and out of the cell

Question 7

Mitochondria

Answer 7

Most energy is released by respiration here

Question 8

Ribosomes

Answer 8

Protein synthesis happens here

Question 9

Cell wall

Answer 9

strengthens the cell – made of cellulose

Question 10

Chloroplasts

Answer 10

Contain chlorophyll, absorbs light energy for photosynthesi

Question 11

Permanent vacuole

Answer 11

filled with cell sap to help keep the cell turgid

Question 12

Sperm

Answer 12

Function is to fertilise an egg.
• Streamlined with a long tail to swim to the egg.
• Acrosome in the head containing enzymes to
digest the egg cell membrane.
• Large number of mitochondria in the mid section
to release energy for movement.

Question 13

Nerve

Answer 13

Function is to carry electrical signals.
• Long to carry signals long distances.
• Branched connections to connect to other nerve
cells and form a network around the body.
• Insulating sheath to enhance transmission of
electrical signals.

Question 14

Muscle

Answer 14

Function is to contract to allow movement.
• Contain a large number of mitochondria to
release energy from respiration for movement.
• Long so that there is enough space to contract.

Question 15

Root hair

Answer 15

Function is to absorb water and minerals from the
soil.
• Hair like projections to increase the surface area.
(Note that root hair cells have no chloroplasts this is
because they do not need them as they are in the soil)

Question 16

Xylem

Answer 16

Function is to carry water and minerals in plants.
• Form hollow xylem tubes made of dead tissue.
• Long cells with walls toughened by lignin.
• Water and minerals flow from the roots towards the
leaves only in one direction in a process called
TRANSPIRATION

Question 17

Phloem

Answer 17

Function is to carry glucose around the plant.
• Form phloem tubes made of living tissue.
• Cells have end plates with holes in them.
• Glucose in solution moves from the leaves to growth
and storage tissues in a process called
TRANSLOCATION.

Question 18

What does cell differentiation mean?

Answer 18

When a cell changes to become specialised.

Question 19

In what stage of an animal’s life cycle do most cells differentiate?

Answer 19

In the early stages.

Question 20

In mature animals when do cells still need to differentiate?

Answer 20

For repair and replacement of cells

Question 21

In what stage of their life cycle do plant cells differentiate

Answer 21

they differentiate throughout their lifecycle.

Question 22

Define the term resolution

Answer 22

The shortest distance between two objects that can be seen clearly.

Question 23

What are the advantages of the electron microscope?

Answer 23

Electron microscopes
have a higher magnification and resolution than light microscopes; scientists
can see more sub-cellular structures.

Question 24

Name the smallest cell structures that can be seen by the light microscope?

Answer 24

Nuclei and mitochondria

Question 25

What are the smallest cell structures that can be seen by the electron
microscope?

Answer 25

Internal structures of mitochondria and chloroplasts.

Question 26

Describe how you would make an onion cell slide.

Answer 26

• Place thin section of onion epidermis onto slide.
• Place a drop of iodine in the middle of the slide to stain the onion.
• Gently lower cover slip onto the onion without trapping air
bubbles.
• Soak up any excess liquid with a paper towell

Question 27

Describe how you would use the light microscope to view onion
cells.

Answer 27

• Switch on the light source and place your slide on the stage.
• Use the lowest objective lens and turn the focusing wheel to move
the lens close to the slide.
• Slowly adjust the focusing wheel until you can see a clear image.
• Increase the magnification by changing the objective lens and refocus.

Question 28

What is ‘binary fission’?

Answer 28

Cell division where two identical cells to the

parent cell are formed

Question 29

Why do you need to sterilise Petri dished and culture mediums before
use?

Answer 29

To kill any unwanted microorganisms.

Question 30

What would you use an inoculating loop for?

Answer 30

To transfer bacteria onto

the agar

Question 31

How do you sterilise an inoculating loop?

Answer 31

By heating in a Bunsen flame