B1- Cell Biology

Question 1

What are the 5 subcellular structures found in plant/ animal cells?

Answer 1

Mitochondria
Cell membrane
Ribosomes
Cytoplasm
Nucleus

Question 2

What are the 3 subcellular structures only found in plant cells?

Answer 2

Chloroplasts
Vacuole
Cell wall (also present in algae cells)

Question 3

What is the function of the nucleus?

Answer 3

Contains genetic material that controls the activities of the cell.

Question 4

What is the function of the cytoplasm?

Answer 4

Where chemical reactions happen- contains enzymes that help speed up rate of reaction.`

Question 5

What is the function of the cell membrane?

Answer 5

Holds cell together and controls what goes in and out of the cell.

Question 6

What is the function of the mitochondria?

Answer 6

Where most of aerobic respiration takes place- Providing energy to the cell.

Question 7

What is the function of the ribosomes?

Answer 7

Where protein synthesis occurs- Found on endoplasmic reticulum.

Question 8

What is the function of the cell wall?

Answer 8

Provides strength and shape to the cell made of cellulose

Question 9

What is the function of the permanent vacuole?

Answer 9

Contains cell sap, improving cells rigidity- found in cytoplasm.

Question 10

What is the function of the chloroplasts?

Answer 10

Where photosynthesis occurs- contains green substance called chlorophyl which absorbs light needed for photosynthesis

Question 11

What is a prokaryotic cell?

Answer 11

A single celled organism- small and simple- DNA not enclosed in nucleus

Question 12

What is a eukaryotic cell?

Answer 12

A cell with membrane bound organelles- complex and bigger than prokaryotic- DNA enclosed in the nucleus

Question 13

What subcellular structures are found in a bacterial cell

Answer 13

Cell membrane
Cell wall (made up of peptidoglycan)
Cytoplasm
Singular strand of DNA
Plasmids

Question 14

What is a plasmid?

Answer 14

Small ring of DNA

Question 15

How do you calculate magnification

Answer 15

Image size/
Real size

Question 16

Describe how to prepare a microscope slide for onion tissue

Answer 16

• Peel of epidermal layer using forceps
• Place sample on drop of water on microscope slide
• Add a few iodine drops to solution
• Lower cover slip onto sample using mounting needle

Question 17

Why is a thin sample used?

Answer 17

To see internal structure of the cell as light can pass through

Question 18

Why is iodine added?

Answer 18

Iodine solution adds contrast- reacts with starch to become blue-black allowing internal structures to be seen.

Question 19

Why is a mounting needle used to lower cover slip?

Answer 19

To ensure no air bulled get trapped

Question 20

How could you measure length of cell viewed under microscope?

Answer 20

Measure using eyepiece graticule and calibrate with stage micrometre.

Question 21

What safety precautions should be considered when carrying out microscopy practical?

Answer 21

Wear goggles when handling iodine solution.

Question 22

What is differentiation?

Answer 22

The process by which a cell becomes specialised- allowing them to carry out different functions.

Question 23

How is the sperm cell specialised?

Answer 23

Specialised for reproduction
-long tail/ streamlined head to help it swim to the egg
- Lots of mitochondria to provide energy
-Carries enzymes in its head to help it penetrate eggs cell membrane

Question 24

How is the nerve cell specialised?

Answer 24

Specialised for rapid signalling
-Axon is long, enabling impulses to be carried along long distances
- Dendrites to branch connections with other nerve cells
-Nerve endings have many mitochondria to supply energy to make neurotransmitters

Question 25

How is the muscle cell specialised?

Answer 25

Specialised for contraction - Proteins (myosin/ actin) slide over each other, causing muscle to contract - Lots of mitochondria, providing energy from respiration for contraction - store glycogen used in respiration

Question 26

How is the root hair cell specialised?

Answer 26

Specialised for absorbing water and minerals - Large surface area for more absorption -Large permanent vacuole affecting speed of water movement from soil to cell -Mitochondria to provide energy for active transport

Question 27

How are xylem cells specialised?

Answer 27

Specialised for transporting substances -Hollow (no end walls( with no subcellular structures to allow water/ nutrients to pass through - thick walls made of lignin to support plant

Question 28

What is a stem cell?

Answer 28

An undifferentiated cell which has the ability to become one of many different types of cell or to produce more stem cells

Question 29

What is fertilisation?

Answer 29

When a sperm cell joins with an ovum (egg cell)- their genetic material combines.

Question 30

Where can stem cells be found?

Answer 30

Bone marrow

Question 31

How can stem cells in bone marrow help cure disease?

Answer 31

They can be injected into others from a donor to cure diseases linked to a lack of bone marrow stem cells such as leukaemia. They can also replace faulty cells such as insulin-making cells for diabetics and nerve cells for paralysed.

Question 32

Why may some people be against stem cell research

Answer 32

- Potential human life -Banned in some countries -religious beliefs

Question 33

Where are stem cells found in plants?

Answer 33

Meristem

Question 34

Why are stem cells from plants useful?

Answer 34

Stem cells from meristems can be used to produce clones of plants quickly/economically. -Rare species can be cloned to protect from extinction. -Crop plants with special features E.g. disease resistance can be cloned to produce large numbers of identical plants for farmers.

Question 35

How large is a centimetre (cm)? (In metres)

Answer 35

1*10 (-2)

Question 36

How large is a millimetre(mm)? (In metres)

Answer 36

1*10 (-3)

Question 37

How large a micrometre(μm)? (in metres)

Answer 37

1*10( -6)

Question 38

How large is a nanometre(nm)? (in metres)

Answer 38

1*10 (-9)

Question 39

Most animal cells are specialised- what does that mean?

Answer 39

They have adapted to carry out a specific function

Question 39

How large is an order on magnitude?

Answer 39

10X

Question 40

How are phloem cells specialised?

Answer 40

Specialised to transport substances - sieve plates and vessel cells (no nucleus) to allow dissolved sugars to pass through interior.