Cell Division

Question 1

what gets stopped by the metaphase checkpoint

Answer 1

.cells with extra chromosomes

Question 2

what checkpoint stops cells with damaged DNA

Answer 2

.G1

Question 3

phases of interphase in cell cycle

Answer 3

G1, S and G2

Question 4

what is checked at S checkpoint

Answer 4

.checking that DNA has been replicated correctly

Question 5

stage with least amount of DNA

Answer 5

G1

Question 6

stage with most amount of DNA

Answer 6

G2

Question 7

stage with highest num of cells

Answer 7

G1

Question 8

Suggest why the use of fluorescent dyes in flow cytometry is inappropriate when analysing red blood
cells.

Answer 8

.they do not contain DNA

Question 9

erthrocytes

Answer 9

.biconcave shape
.no nucleus
.flexible to allow them to squeeze through narrow capillaries

Question 10

Neutrophils

Answer 10

.multi-lobed nucleus
.makes it easier to squeeze
through small gaps
.many lysosomes
.many mito
.well developed cytoskeleton

Question 11

Palisade cells

Answer 11

.thin cell walls
.allowing rapid
diffusion of carbon dioxide

Question 12

sperm adaptations

Answer 12

.flagella allows sprem to move towards egg
.many mito to supply ATP for movement
.acrosome to penetate egg

Question 13

cell had stopped dividing at the G2 checkpoint..
WHY?

Answer 13

.larger num of organelles
.more DNA
.no visible chromosomes
.nuclear membrane present

Question 14

roles of mitosis

Answer 14

.growth
.repair
.asexual reproduction
.production of new stem cells
.producing gametes from haploid cells

Question 15

Suggest why Hydra reproduces asexually when conditions are favourable.

Answer 15

.genetically identical offspring
.produced rapidly
.find conditions good

Question 16

drawing cells

Answer 16

.label what you see- even cyto
.label colour of components
.make sure same size as example

Question 17

mitosis

Answer 17

prophase:
.chromosomes condense
.chromosomes have become visible
.nuclear envelope and nucleolus disappear

anaphase:
.spindle fibres shortening
.chromatids separating and being pulled to opposite sides of the cell

telophase:
.chromatids been pulled to oppo sides
.new cell mem visible at the centre of the cell
.cell begins to divide(cytokinesis)

Question 18

why does a zygote undergo mito not meio

Answer 18

.zygote needs to grow
.which needs genetically identical cells
.only made by mito

Question 19

meiosis increased genetic variation

Answer 19

prophase 1:
.crossing over of alleles between non-sister chromatids
.base sequence is altered

metaphase 1:
.independent assortment
.homologous chromosomes line up at the centre of cell
.either one of the homologous pair can end up in either daughter cell
.each chromosome of Hpair is genetically diff

meta 2:
.same as meta 1 but with chromatids

Question 20

how how xylem cells produced

Answer 20

.in meristems
.by differentiation

Question 21

role of opsonin

Answer 21

.binds to antigen on pathogen and binds it to phagocyte

Question 22

Describe the changes that must occur inside these stem cells as they differentiate to form
erythrocytes.

Answer 22

.synthesise alot of haemoglobin
.remove organelles related to protein synthesis

Question 23

ways in which the use of embryonic stem cells in research has practical benefits to biological knowledge.

Answer 23

.test how effective new medical drugs are
.test for side affects of new drugs
.studied to see how they develop into diff cell typess
.studied to find out what can make it fail to work
properly in certain diseases

Question 24

muscle tissue vs muscle

Answer 24

.tissue = group of cells which contact together

.muscle = organ that consists of muscle tissue and other tissue working together

Question 25

benefit to plants of internal transport systems.

Answer 25

.SA:VOL ratio too small
.diffusion is not suffcient
.so it ensures that molecules reach all tissues

Question 26

come back to Q.49ii

Question 27

why is a plant leaf an organ

Answer 27

.organs are
.a collection of tissues
.which carry out a function
.leaves have:
.phloem and xylem etc
.which carry out photosynthesis and gaseous exchange

Question 28

why cant podocytes undergo mitosis

Answer 28

.they are in G0 phase
.shape is too irregular so cannot divide
.spindle fibres cannot form
.number of gaps will form
.

Question 29

features of adult stem cells make them suitable for regeneration

Answer 29

.multipotent
.they can differntiate into any cell type

Question 30

difference between the effects of cyanide and fluoride
on respiration in sperm?

Answer 30

.cyanide stops aerobic respiration

.fluoride stops anaerobic respiration

Question 31

role of embryonic stem cells in the development of the embryo.

Answer 31

.they are undifferentiated
.can differentiate into any cell type of developing foetus

Question 32

why the cells of the inner cell mass are not totipotent stem cells.

Answer 32

.they cannot form whole organism
.cannot give extra-embryonic tissue
.are pluripotent

Question 33

structures involved in preventing entry of pathogens into the body

Answer 33

.skin
.mucus
.goblet cells
.platelets

Question 34

how golgi is useful in goblet cells

Answer 34

.folds and packages protein

Question 35

how Erythrocytes and neutrophils and Squamous and ciliated epithelial cells
specialised for its function

Answer 35

erythrocytes:
.biconcave shape-space for O2
.no nucleus-space for O2
.contain haemoglobin
.transport oxygen and CO2

neutrophil:
.many lysosomes
.digestive enzymes
.can undergo phagocytosis
.can destroy pathogens

squamous epithelial:
.one cell thick- short diff dist
.tight for rapid diffusion

cilitated epithelial:
.have cilia move in rhythm to move mucus
.have goblet cells to screte mucus

Question 36

pro and cons of red blood having no nucleus

Answer 36

pro:
.can carry more oxygen/haemoglobin
.can squeeze through capillaries

cons:
.limited life span
.cannot undergo mito
.no protein synthesis
.no mito for respiration

Question 37

why erythrocytes do not make use of any of the oxygen that they are transporting

Answer 37

.oxygen is bound to haemoglobin
.lack mitochondria
.so no aerobic respir
.so moves via mass flow

Question 38

how gills are adapted for efficient gas exchange.

Answer 38

.many lamellae = provide large SA
.secondary lamellae on main lamellae = larger SA
.short distance between blood and water
.blood maintains diffusion gradient

Question 39

how xylem vessel
elements are produced from stem cells

Answer 39

.by differentiation
.cell elongation
.deposition of lignin
.end walls break down