GCSE Revision 1/7

Question 1

Nucleus

Answer 1

Carries instructions for making proteins

Question 2

Cytoplasm

Answer 2

Where organelles are suspended, and where chemical reactions take place

Question 3

Cell membrane

Answer 3

Controls movement of substances into and out of the cell

Question 4

Mitochondria

Answer 4

Where energy is transferred during aerobic respiration

Question 5

Ribosomes

Answer 5

Where protein synthesis occurs

Question 6

Cell wall

Answer 6

Support

Question 7

Chloroplasts

Answer 7

Contain chlorophyll for photosynthesis

Question 8

Permanent vacuole

Answer 8

Stores cell sap keeping the cell rigid

Question 9

Prokaryotic cells features (5)

Answer 9

Cell membrane, cell wall, no nucleus (plasmids instead), cytoplasm, slime capsule/flagella

Question 10

Specialisation in Nerve cells (4)

Answer 10

Many dendrites to make connections to other nerve cells
Axons to carry impulses from one place to another
Synapses which pass impulses to other cells through chemicals
Mitochondria in synapses to transfer energy needed for neurotransmitters

Question 11

Specialisation in muscle cells (3)

Answer 11

Special proteins that slide over eachother
Many mitochondria to transfer required energy for chemical reactions
Store of glycogen that can be broken down and used in respiration

Question 12

Specialisation in sperm cells (4)

Answer 12

Long tail that propels the sperm
Middle section full of mitochondria to transfer energy needed to move
Acrosome to store digestive enzymes to break down outer layers of the egg (at the tip)
Large nucleus containing the genetic information

Question 13

Specialisation in root hair cells (3)

Answer 13

Large SA for water to move into the cell
Large permanent vacuole to speed up movement of water
Mitochondria to transfer energy for active transport of mineral ions

Question 14

Specialisation in photosynthetic cells (3)

Answer 14

Chloroplasts with chlorophyll to trap light needed for photosynthesis
Often found in continuous layers in the leaf and outer layers of stems (at the surface)
Have a large permanent vacuole that helps keep the cell rigid

Question 15

Specialisation in xylem cells [transport of water and mineral ions and structural support] (2)

Answer 15

Long hollow tubes for water and mineral ions to move up through
Spirals of lignin make the xylem tubes very strong

Question 16

Specialisation in phloem cells (3)

Answer 16

Sieve plates (made from broken down cell walls) to move phloem sap by translocation through the plant
Companion cells with mitochondria that transfer energy to aid in this movement of phloem sap

Question 17

Osmosis across

Answer 17

Partially permeable membrane

Question 18

Same concentration of solutions

Answer 18

Isotonic

Question 19

More concentrated solution

Answer 19

Hypertonic

Question 20

Less concentrated solution

Answer 20

Hypotonic

Question 21

Turgor pressure

Answer 21

When no more water can enter the cell

Question 22

How does a cell become turgid (4)

Answer 22

Water moves in by osmosis
Vacuole swells
Cytoplasm is pressed against the cell wall
Cell becomes rigid

Question 23

What is the opposite of turgid

Answer 23

Flaccid

Question 24

Plasmolysis

Answer 24

When plant cells lose so much water that the vacuole and cytoplasm shrink and the cell membrane pulls away from the cell wall

Question 25

Active transport

Answer 25

Diffusion against a concentration gradient- requires energy

Question 26

How does active transport occur (3)

Answer 26

Molecule binds to transport protein Protein rotates and releases molecule inside cell (E) Cell rotates back again (E)

Question 27

Relationship between SA and V depending on size

Answer 27

As size increases, the ratio decreases

Question 28

Cell cycle stage 1 - Interphase (3)

Answer 28

The longest stage, cells grow, increase in mass, and carry out normal activities The cells then replicate their DNA to make two copies of of every chromatin strand in the nucleus They also make more sub-cellular structures in the cell

Question 29

Cell cycle stage 2 - Mitosis (5)

Answer 29

Chromatin condenses and coils to form chromosomes Nucleus Disintegrates Chromosomes line up in the centre of the cell Spindle apparatus pulls identical chromosomes to opposite ends of the cell Nucleus returns

Question 30

Cell cycle stage 3- Cytokinesis (1)

Answer 30

Cytoplasm and the cell divides in half to form two identical daughter cells

Question 31

How many chromosomes do human body cells have

Answer 31

46 (23 pairs) DIPLOID

Question 32

What are egg and sperm cells also known as

Answer 32

Gametes

Question 33

How many chromosomes do egg and sperm cells have

Answer 33

23 each HAPLOID

Question 34

Stem Cells and where are they found in animals and plants

Answer 34

Cells that haven't yet specialised. Found in animal embryos and plant meristems

Question 35

Where do adult stem cells do

Answer 35

Provide a backup of specialised cells if the ones that were made at birth don't work anymore (these can't divide by mitosis)

Question 36

How can you make more specialised cells without stem cells?

Answer 36

Embryo cloning- making a clone of a person and culturing the embryonic stem cells to create specialised cells

Question 37

What can stem cells help with (2)

Answer 37

Paralysis by differentiating into new nerve cells Diabetes- producing cells that are sensitive to blood sugar and can produce insulin

Question 38

What is a meristem

Answer 38

Actively dividing groups of plant tissues found at the tips of plants

Question 39

How can stem cells be used in plants (4)

Answer 39

Save rare plants from extinction Create genetically identical plants for scientific research Produce large numbers of exotic plants for sale Plants with special features can be cloned

Question 40

Stem cell dilemmas (4)

Answer 40

Violation of the embryo's rights (ethical) Not interfere with the natural processes of reproduction (religious) A lot of money is wasted on research which could be used in other things (ethical and social) Embryonic stem cells could cause cancer as they divide rapidly

Question 41

Therapeutic cloning

Answer 41

A process where an embryo is produced that is genetically identical to the patient so the cells can then be used in medical treatment