Biology topic 2

Question 1

Rough ER

Answer 1

Ribosomes on surface
Flattened sacs and membrane bound
Folds and processes proteins from ribosomes

Question 2

Smooth ER

Answer 2

Membrane bound sacs
Synthesises and processes lipids/steroids

Question 3

Golgi apparatus

Answer 3

Fluid-filled flattened/curves sacs- cisternae
Surrounded by vesicles
Sorts, processes + packages proteins/lipids
Produces lysosomes

Question 4

Mitochondria

Answer 4

Double membrane
Inner membrane- cristernae
Matrix- enzymes for cellular respiration

Question 5

Centrioles

Answer 5

Hollow cylinders- ring of microtubules
Involved in cell division

Question 6

80S ribosomes

Answer 6

Large and small subunit
Site of protein synthesis
Contains RNA

Question 7

Lysosomes

Answer 7

Vesicles containing digestive enzymes
Single membrane

Question 8

Chloroplasts

Answer 8

Protein synthesis in plant cells

Question 9

Vacuole

Answer 9

Storage of substances in plant cells

Question 10

Tonoplast

Answer 10

Semi-permeable membrane

Question 11

Cell wall (pro)

Answer 11

Made of peptidoglycan
Strength + support

Question 12

Slime capsule (pro)

Answer 12

Slimy layer- retain moisture + adhere to surfaces

Question 13

Plasmid (pro)

Answer 13

Circular piece of DNA

Question 14

Flagellum (pro)

Answer 14

Movement

Question 15

Pili (pro)

Answer 15

Hair like
Attach + allow plasmids to move cell to cell

Question 16

70S ribosomes (pro)

Answer 16

Large + small subunit
Proteinsynthesis

Question 17

Mesosomes (pro)

Answer 17

Infoldings of inner membrane
Contain enzymes for respiration

Question 18

Nucleoid (pro)

Answer 18

Contains genetic material

Question 19

Lytic cycle

Answer 19

1. Attachment onto host cell
2. Penetration
3. Hijacks host cell functions
4. Viral DNA/RNA replicated, new proteins (capsids)
5. Host cell lyses releasing viruses

Question 20

Lysogenic cycle

Answer 20

Inserts DNA in form of provirus into host cell DNA
DNA replicated via cell division of host cell
Provirus remains dormant —> virus produces repressor proteins (inhibit transcription of provirus)
Host cell damaged/weakened —> dormant viruses enter ltic cycle

Question 21

Function of antivirals

Answer 21

Inhibit virus replication

Question 22

Gram positive bacteria vs gram negative bacteria

Answer 22

Gram +ve has thick layer of peptidoglycan vs gram -ve that has thin layer
Gram +ve outer membrane absent
Gram -ve outer membrane present with lipopolysaccharide attached.

Question 23

Spermatogenesis process

Answer 23

1. Primordial germ cell undergo several divisions of mitosis- producing spermatogonia
2. One spermatogonia grow to produce primary spematocyte
3. Meiosis 1 to produce 2ndary spermatocytes (23 X)
4. Meiosis 2 to produce spermatids (23)
5. Growth + differentiation –> speratozoa

Question 24

Function of mitosis

Answer 24

Produces 2 genetically identical daughter cells for growth, repair and asexual reproduction

Question 25

Function of meiosis

Answer 25

Production of haploid gametes and maintenance of chromosome number

Question 26

Oogenesis process

Answer 26

1. Primordial germ call divides by mitosis to produce oogonia
2. Growth of one oogonia to form primary oocyte (other 3 break down)
3. Occurs once per cycle, primary oocyte undergoes meiosis 1 to produce a secondary oocyte and first polar body.
4. Undergo meiosis 2, ovum formed + polar bodies break down

Question 27

Process of fertilisation

Answer 27

1. Sperm head contacts zona pellucida –> acrosome rxn
2. Sperm head fuses with cell membrane of egg cell, sperm nucleus enters egg cell
3. Cortical rxn occurs –> zona pellucida hardens to prevent polyspermy
4. Nuclei fuse, full set of chromosomes restored (46) and diploid zygote formed.