Chapter 1: Cell Structure and Organisation

Question 1

Name the parts of an animal cell

Answer 1

Cell membrane
Cytoplasm
Nucleus
Small and numerous vacuoles
Mitochondria

Question 2

Name the parts of a plant cell

Answer 2

Cell membrane
Cytoplasm
Nucleus
Cell wall
Chloroplasts
Large central vacuole
Mitochondria

Question 3

Describe the cell membrane (+function)

Answer 3

-Partially permeable
-Holds contents of the cell in place
-Regulates the movement of substances in and out of the cell

Question 4

Describe the cytoplasm (+function & involved structures)

Answer 4

-Where most cell activities occur
-Contains RER, SER, Golgi body/apparatus and ribosomes

Question 5

Describe the nucleus (+function & structures involved)

Answer 5

-Controls all cell activities
-Contains genetic material
-Contains
1. Chromatin
2. Nuclear envelope/membrane
3. Nucleolus
4. Nucleoplasm

Question 6

Describe the cell wall (+function)

Answer 6

-Made of cellulose
-Fully permeable
-Protects plant cells from injury
-Gives cell a rigid shape

Question 7

Describe the Rough Endoplasmic Reticulum (+function)

Answer 7

-Continuous w/ nuclear membrane
-Appears rough, bc ribosomes are attached to its outer surface
-TRANSPORTS/ SYNTHESISES proteins to Golgi apparatus for secretion out of the cell

Question 8

Describe the Smooth Endoplasmic Reticulum (+function)

Answer 8

-Connected to RER
-No ribosomes (and more tubular)
-SYNTHESISES substances e.g. fats & steroids(e.g. sex hormones-> androgens and estrogens)
-Involved in detoxification (liver)

Question 9

Describe ribosomes (+function)

Answer 9

-Small round structures
-Needed to synthesise proteins
-Free ribosomes
->Synth. proteins used within cell
-Ribosomes on RER
->Synth. proteins transported out of cells

Question 10

Describe the Golgi body/apparatus (+function)

Answer 10

-Consists of flattened spaces surrounded by a membrane (spotify shape)
-STORES and MODIFIES substances made by ribosomes on ER
-PACKAGES the substances in VESICLES for secretion out of the cell

Question 11

Summarise movement of substances out of the cell

Answer 11

1. Vesicles containing substances made in ER (RER & SER) pinch off from the ER
2. Vesicles fuse w/ Golgi body/apparatus
3. Substances in vesicles are released into the Golgi body and are MODIFIED
4. Secretory vesicles containing modified substances pinch off from Golgi body and move towards cell surface membrane
5. Secretory vesicles fuse w/ cell surface membrane and release contents to exterior of cell

Question 12

Describe mitochondria (+function)

Answer 12

-Site of aerobic respiration where glucose is oxidised to release energy

Question 13

Application: Which cells of the body contain larger amounts of SER?

Answer 13

Liver cells-> involved in detoxification
Cells in testes & ovary-> synthesises sex hormones

Question 14

State differences between a plant cell and an animal cell.

Answer 14

ANIMAL CELL: No cell wall
PLANT CELL: Cell wall

ANIMAL CELL: Chloroplast absent
PLANT CELL: Chloroplast present

ANIMAL CELL: Numerous temporary vacuoles
PLANT CELL: A large central vacuole

Question 15

Function of chloroplast?

Answer 15

Contains chlorophyll which absorbs light energy to carry out photosynthesis

Question 16

Purpose of large central vacuole?

Answer 16

-Store substances within the cell
-Animal cells->water & food substances
Plant cells->cells sap (made up of sugars, mineral salts and amino acids)

Question 17

How is a RBC’s structure adapted to its function?
(Structure to function qn)

Answer 17

Function: Transport oxygen from lungs to all parts of the body

Structure:
1. Haemoglobin present in cytoplasm of RBC->binds to O2 to transport it around the body
2. No nucleus->enables cell to maximise space to store more haemoglobin
3. Circular biconcave shape->increases surface are to volume ratio, increases rate of diffusion of oxygen in an out of the cell
4. Flexible->turn bell-shaped to allow cell to travel along tin blood capillaries

Question 18

How is the muscle cell adapted to its function?
(Structure to function qn)

Answer 18

Function: Contract & relax to bring about movement

Structure:
1. Elongated and cylindrical shape
2. Contains many nuclei
3. Contains many mitochondria->release more energy for contraction of the muscle cell
4.Contains many contractile protein fibres
->contract and relax to bring about movement

Question 19

How is the root hair cell adapted to its function?
(Structure to function qn)

Answer 19

Function: To absorb water & mineral salts from the soil into the roots

Structure:
1. Long and narrow extension/protrusion-> increases surface area to volume ratio, faster rate of absorption of water and mineral salts
2. More mitochondria (compare to general plant cells)->higher rate of aerobic respiration for release of more energy to carry out active transport of mineral salts from soil sol. to root hair cell