cellular division/organisation

Question 1

Name the type of tissue that undergoes cell division to form these undifferentiated plant cells.

Answer 1

meristematic

Question 2

A pair of chromosomes that contain genes for the same characteristics.

Answer 2

homologous (chromosomes) OR homologue(s) ;

Question 3

A group of organs working together to perform an essential function.

Answer 3

(organ) system ;

Question 4

A type of cell division that produces genetic variation.

Answer 4

meiosis ;

Question 5

Name the process of asexual reproduction in yeast.

Answer 5

budding

Question 6

Outline the process of asexual reproduction in yeast.

Answer 6

mitosis ;
swelling / bulge, in (surface of) the cell ;
nucleus moves into, swelling / bulge / bud ;
idea that, bulge / bud, nips / pinches / breaks off / cleaves ;
ref to uneven distribution of cytoplasm ;

Question 7

Even when the environmental conditions are perfect, one yeast cell rarely produces the calculated number of potential new cells.
Suggest why the reproductive potential of the yeast cell is not reached.

Answer 7

new bud cannot occur, on / close to, old scar ;
not enough space between scars for another bud ;
yeast cell not a true sphere ;
(gene) mutation / DNA damage ;

Question 8

Yeast cells separate after cell division. In a multicellular organism, the cells do not separate but become organised to form the body structure.Describe how the cells in a multicellular organism are organised.

Answer 8

(cells) differentiate(d) / specialise(d) ;
(groups of) cells form tissue(s) ;
(groups of) tissues form organ(s) ;
(groups of organs) form organ system(s) ;
(group of) cells / tissues / organs / organ systems, work
together / interact ;
named example of a tissue / an organ /an organ system ;
QWC
differentiate, specialise / specialize, tissue, organ, organ
system

Question 9

Name the type of cell division that occurs in asexual reproduction.

Answer 9

mitosis

Question 10

Before the division of the nucleus of a cell, the genetic material must replicate. Explain why this is essential.

Answer 10

idea that:
cells, genetically identical / have same DNA ;
so both (daughter) cells receive a full, copy / complement ;

Question 11

Unlike yeast, the nuclei of most eukaryotic organisms contain homologous pairs of chromosomes.Explain what is meant by a homologous pair of chromosomes

Answer 11

1 one maternal and one paternal / AW ;
2 carry same genes ;
3 carry, same / different, alleles ;
4 (usually) same / similar, length ;
5 centromere in same position ;
6 same banding pattern ;
7 pair up in meiosis / form bivalent ;

Question 12

State what is meant by the term tissue.

Answer 12

a, group / collection, of cells ;
(cells) specialised / AW ;
to perform a function(s) / working together ;

Question 13

The liver is an organ.

Explain what is meant by the term organ.

Answer 13

idea of more than one (type of) tissue ;

working together / performing a function(s) ;

Question 14

Using the mammalian gaseous exchange system as an example, explain how the different cells and tissues enable the effective exchange of gases.

Answer 14

C1 thin / squamous, epithelium ;
C2 thin endothelium (of capillary) ;
F1 (provides) short diffusion distance / described ;
F2 ref to surfactant (from epithelial cells) ,
 reducing surface tension /
 preventing alveoli collapsing ;
C3 blood / red blood cells / erythrocytes ;
F3 transports (named) gas(es) , to / from ,
 exchange surface / alveoli ;
C4 diaphragm / intercostals , muscles ;
F4 (maintains / creates) diffusion / concentration ,
gradient ;
C5 ciliated epithelium / goblet cells / ciliated cells ;
F5 idea of: protection from / removal of ,
 dust / bacteria / pollen / spores ;
C6 cartilage ;
F6 hold airway open ;
C7 smooth muscle ;
F7 constrict / control diameter of , airway / blood vessel ;
C8 elastic , fibres / tissue ;
F8 for recoil / aiding ventilation ;
C9 macrophage / neutrophil ;
F9 engulf / destroy pathogens
 or
 protect from infection ; 
QWC
epithelium / epithelial, endothelium,
cartilage, diffuse / diffusion,
gradient, goblet,
ciliated, concentration,
squamous, macrophage,
neutrophil, surfactant,
muscle, erythrocyte

Question 15

Name the type of nuclear division that occurs in a plant meristem.

Answer 15

mitosis mitotic

Question 16

State one way in which the products of meiosis are different from the products of nuclear division in meristematic tissue.

Answer 16

in meiosis
(cells produced are) not genetically identical ;
one set of chromosomes / haploid ;
(they are) gametes ;
four cells produced ;

Question 17

Name the type of nuclear division that produces two genetically identical nuclei.

Answer 17

mitosis mitotic division

Question 18

During interphase the genetic material is copied.State two other processes that occur during interphase.

Answer 18

1 checking, genetic material / DNA / chromatin /
chromosome(s) / genes, (for errors) ;
2 protein synthesis ;
3 synthesis / replication / increase in number of,
organelles / named organelle ;
4 ATP production / respiration ;
5 cell growth / increase in cell, volume / size ;

Question 19

Suggest two ways thatcell division in plants differs from cell division in animals.

Answer 19

in plant
(cell), plate / wall, forms (between new cells) ;
idea of :
cytokinesis starts from middle of cell ;
(only) occurs in meristem ;
no centrioles ;

Question 20

Name the process in which a cell becomes specialised.

Answer 20

differentiation

Question 21

Neutrophils are phagocytic blood cells that can engulf and digest foreign cells found in the blood.Describe how the ultrastructure of a neutrophil is specialised to enable it to perform this function.

Answer 21

1 (many) lysosomes / vesicles containing enzymes ;
2 (many) microfilaments / microtubules
OR
ref to, extensive / well developed, cytoskeleton ;
3 (many) ribosomes / (a lot of) rough endoplasmic
reticulum / (a lot of ) RER ;
4 (many) mitochondria ;
5 (lots of) Golgi ;
6 (many) receptor (sites) on, cell surface / plasma ,
membrane
QWC
lysosome(s), ribosome(s), rough endoplasmic reticulum,
mitochondria / mitochondrion, Golgi/golgi,
microfilaments/microtubules / cytoskeleton,
cell surface membrane / plasma membrane.

Question 22

Outline the process of budding in yeast.

Answer 22

nucleus divides / mitosis ;
idea of :
cell, swells on one side / bulges ;
nucleus / cytoplasm / organelles, move into,
bud / bulge ;
pinches off / cell wall forms, (so bud becomes
a separate cell) ;

Question 23

Explain what is meant by the term tissue.

Answer 23

collection / group, of cells (of one or more types) ;
(cells), working together OR with, common / same,
 function ;

Question 24

Name one type of epithelial tissue found in the lungs.

Answer 24

squamous / ciliated ;

Question 25

Explain why the lungs can be considered to be an organ.

Answer 25

(organ is) a collection of tissues / named tissues ;

(working together) to enable gas exchange / AW ;

Question 26

State what is meant by the term stem cell .

Answer 26

a cell that is, unspecialised / not differentiated ;
capable of, division / mitosis ;
able to, differentiate / specialise / become other cell types ;

Question 27

State three reasons why mitosis is important to organisms.

Answer 27

growth (of tissue / organism) ;
replace (cells) / repair (tissues) ;
asexual reproduction/cloning / producing genetically identical
cells ;
maintain chromosome number in all cells ;

Question 28

Suggest two advantages, other than an increased probability of survival, of using umbilical cord blood stem cells instead of bone marrow stem cells in transplant procedures.

Answer 28

1 greater availability of cord cells / more likely to find
donors;
2 easier to harvest / no pain for donor ;
3 cells at earlier stage of development ;
4 can be stored for future, use/repair / gene therapy, of
donor ;
5 slightly mismatched cord cells work (almost) as well as
marrow cells ;