Cell division, Cell Diversity & Cellular Organisation Flashcards
Animal cells
Means of cell division- Cytokinesis
Presence of nucleus-yes
Material in cell wall-none
Presence if ribosomes-yes
plant cells
Means of cell division- cytokinesis
Presence of nucleus- yes
Material in cell wall- cellulose
Presence of ribosomes-yes
Yeast cells
Means of cell division- budding
Presence of nucleus-yes
Material in cell wall-chitin
Presence of ribosomes-yes
Bacterium
Means of cell division-binary fission
Presence of nucleus-no
Material in cell wall-peptidoglycan
Presence of ribosomes-yes
Type of tissue that undergoes cell division in tips of roots and shoots to form undifferentiated plant cells
Meristem
Some Features not found in xylem vessel
Nucleus
Cytoplasm
Cross/end cell walls
How structure of cell walls in xylem vessels would differ from the cell walls of the undifferentiated meristem
Thicker
Lignified
Contain bordered pits
Two types of cells that can be found in phloem tissue
Sieve tube elements
Companion cells
+
Parenchyma
Ways in which genetic variation is produced, including the role of nuclear division
A1. Independent assortment/random segregation of homologous chromosomes
A2.in, metaphase I/meiosis I
A3.of chromatids in,metaphase II/meoisis II
A4.So homologous chromosomes have different alleles
A5.produces large number of allele combinations
C1. Crossing over/formation of chiasmata
C2. In Prophase I/meiosis I
C3. So chromatids will have new combinations of alleles
C4.amount of variation depends on distance between crossover points
M1.mutation
M2.changes the (DNA) nucleotide/base sequence
M3.DNA checks during duplication did not recognise damage
M4.diferences in primary sequences
N1.non-disjunction
N2.homologous chromosomes do not seperate (In metaphase I)
N3. One, more/less ,chromosome present
F1.Random,mating/fusion of gametes/feetilisation
F2.gametes are not genetically identical
F3.produces large number of allele combinations
Cell signalling
Communication between cells
2 examples of communication between cells that occur during life cycle of D.discoideum
1.attraction of cells to folic acid from bacteria
2.attraction of cells to eachother bt cAMP
+
3.coordinated movement in grex
4.differentiation of grex cells in response to DIF
Suggest how plasma membrane of D.discoideum is adapted for cell communication
Contains receptors/glycoproteins/glycolipids
For folic acid/cAMP/DIF
Type of cell division in plant growth
Mitosis
Metaphase
Four chromosomes on equator
New growth in stem or trunk comes from cambium
Explain why the new branches are seen growing from abposition just under bark of cut suface
This is where cambium is found
Mitosis occurs in cambium to produce new cells for growth
New cells differentiate into xylem and phloem
Xylem supplies water for cell elongation/cell growth
Phloem supplies assimilates for energy/growth/respiration
Name one other location where growth occurs in a plant
1.tip/apex of shoot/root
+
2.meristem
3.bud
Lenticels allow gases to diffuse into living tissues of trunk
Suggest why lenticels are essential to the survival of large multicellular plants and explain why similar structures are not found in large multicellular animals
Allow oxygen to reach cells/tissues under bark
For aerobic respiration
Animals transport oxygen in blood/circulation/transport system
Plants do not transport much oxygen in transport system
Oxygen not supplied from leaves as stomata only open in day/no leaves in winter
Link up
Independent assortment –> Metaphase I & II
Formation of the spindle aparatus –>Prophase I
Seperation of sister chromatids –> Anaphase 2
Formation of nuclear membranes –> Telophase II
Chromosomes pulled to opposite poles –> Anaphase 1
Explain why meiosis needs to have twice as many stages as mitosis
To halve chromosome numbers/ have chromosome numbers reduce from 2n to n
To seperate homologous pairs of chromosomes and sister chromatids
Because DNA previously replicated/ chromosomes are.two chromotids at start
What feature of DNA molecule is changed as a result of mutation
Sequence/order of bases/nucleotides
Possible effects that mutation can have on the structure of a protein
Different primary/secondary/tertiary structure
Protein shorter due to deletion/stop codon OR
Longer due to insertion/duplication
Protein unchanged due to silent mutation
Function is lost/worse/better
