The Cell

Question 1

Molecules combine to form

Answer 1

cells

Question 2

groups of similar cells

Answer 2

tissue

Question 3

different tissues join together to form

Answer 3

organs

Question 4

Related organs with a common function form

Answer 4

organ system

Question 5

all cells arise via

Answer 5

cell division

Question 6

describe the plasma membrane - 2 points

Answer 6

thin but sturdy/flexible barrier, fluid mosaic model - phospholipids (heads = phosphates, tails = fatty acids) and proteins

Question 7

Integral proteins

Answer 7

embedded across whole membrane, some = channels for transporting substances, others = chains of carbs to identify and respond to dangerous cells

Question 8

Peripheral proteins

Answer 8

loosely attach to membrane, easily separated

Question 9

Role of plasma membrane - 4 points

Answer 9

separates internal parts of cell from external environment, facilitates contact with other cells/substances, receptors for hormones/chemicals/ABs, selective barrier - substances in and waste out

Question 10

factors affecting permeability - size of mols

Answer 10

large (proteins) = unable to pass through, small (water/AAs) = can

Question 11

factors affecting permeability - solubility in lipids

Answer 11

dissolve easily (o2) = readily pass through because mainly lipid molecules

Question 12

factors affecting permeability - charge on ions

Answer 12

ions = opposite charge to membranes and are therefore attracted to it and pass through easily, ion of same charge = repelled

Question 13

factors affecting permeability - presence of carrier molecules

Answer 13

integral proteins attract and transport substances regardless of size/ability/charge

Question 14

4 Passive processes

Answer 14

diffusion/osmosis/filtration/dialysis

Question 15

An active process

Answer 15

use of ATP

Question 16

ATP stands for

Answer 16

Adenosine Triphosphate

Question 17

Describe nucleus and explain role of nucleus - 3 points

Answer 17

largest structure in cell, double nucleus membrane - with pores to allow passage in/out and for communication with ER in cytoplasm, contains all genetic material for cell growth/division/reproduction

Question 18

Describe nucleolus and explain role of nucleolus - 5 points

Answer 18

spherical, composed of RNA/protein, where DNA is found, appears threadlike = chromatin, then shortens during cell division and coils = chromosomes

Question 19

Describe the cytoplasm - 2 points

Answer 19

thick/elastic fluid, site of chemical reactions and synthesis of new substances

Question 20

Role of cytoplasm - 3 points

Answer 20

facilitates excretion of waste, contains cytoskeleton - network of microfilaments/microtubules providing support/shape - also allows movement of entire cell and structures in cytoplasm

Question 21

Describe and explain role of ribosomes - 2 points

Answer 21

found attached to outer surface of nuclear membrane/ER, site of protein synthesis - used/exported

Question 22

Describe the 2 types of ER (Endoplasmic Reticulum)

Answer 22

Granular - contains ribosomes, Agranular - no ribosomes

Question 23

General Role of ER - 3 points

Answer 23

allows exchange/transport of material in cell, provides surface for chemical reactions, storage area for synthesised molecules

Question 24

Describe role of Granular ER - 2 points

Answer 24

processes/sorts proteins, synthesises/packages proteins with Golgi Apparatus

Question 25

Describe role of Agranular ER - 2 points

Answer 25

network of tubules, synthesises lipids/glycogen/steroids

Question 26

Describe and explain role of Golgi Apparatus - 3 points

Answer 26

4-8 flattened sacs = cristernae, found close to nucleus and Granular ER, process/sort/deliver proteins

Question 27

Describe mitochondria - 3 points

Answer 27

smooth outer surface, inner folds = cristae - provide increased surface area for chemical reactions

Question 28

Explain role of mitochondria - 3 points

Answer 28

produces ATP (stores energy for cellular activities) during aerobic respiration, found in large numbers where there are active cells, able to self-replicate when an increase of ATP is required

Question 29

Describe a centrosome - 3 points

Answer 29

located near nucleus, contains a pair of centrioles, made up of micro-tubule triplets and protein tubulin

Question 30

Explain role of centrosome - 2 points

Answer 30

organising centre for growth of mitotic spindle, critical for/in cell division and reproduction

Question 31

Describe lysosomes - 2 points

Answer 31

membrane-enclosed spheres, form from Golgi apparatus

Question 32

Explain role of lysosomes - 4 points

Answer 32

the cells digestive system - contains digestive enzymes which break down complex molecules, digest bacteria, break down damaged cells (autolysis)

Question 33

Describe and explain role of a vacuole - 3 points

Answer 33

storage bubble, mass of fluid surrounded by membrane, stores nutrients/waste products

Question 34

Describe and explain role of flagella - 3 points

Answer 34

projections from cell surface, contains cytoplasm and bound by plasma membrane, co-ordinated movement causes steady movement across its surface (e.g. ciliated cells move mucus with trapped bacteria from respiratory tract)

Question 35

Explain the purpose of cell division - 2 points

Answer 35

for growth, to replace damaged/diseased/worn out cells

Question 36

2 types of cell division

Answer 36

somatic and reproductive

Question 37

cell division involves 2 types of division -

Answer 37

nuclear and cytoplasmic

Question 38

sex cells

Answer 38

gametes