F211-The Cell Cycle & Life Cycles Flashcards
State the processes that occur during interphase
~DNA replication
~checking of DNA/chromosomes/genes for errors
~protein synthesis
~replication of organelles
~ATP production/respiration
~cell growth/increase in cell volume/size
Describe the roles of Mitosis
~makes cells ~creates genetically identical cells ~replacement of cells which are genetically identical and therefore perform the same function growth of tissues ~repair of tissues ~asexual reproduction
State what happens in Interphase
It is made up of G1, S and G2
G1- protein synthesis, organelles replicated & ATP required
S- DNA replication, ATP required
G2- cell growth, cell increases in size
What are the stages of Mitosis?
Prophase, Metaphase, Anaphase, Telophase and Cytokinesis
What is the defining feature of a cell in interphase under a microscope?
- There are no visible chromosomes
- There is a dark and large nucleus/Nucleolus
His many chromosomes for the nuclei of our cells contain?
46 chromosomes arranged into 23 pairs.
Write the diploid number of chromosomes in terms of n
2n
Write the haploid number of chromosomes in terms of n
n
Define Haploid
A cell or organism that has just one copy of each chromosome
Define Diploid
Cells or organisms that have two copies of each chromosome in their nucleus
Explain what is meant by a homologous pair of chromosomes
- one maternal and one paternal chromosome.
- carry the same genes.
- carry the same or may carry different alleles (same length).
- the centromere is in the same position.
- they have the same banding pattern
(They pair up in meiosis to form a bivalent)
Explain why the genetic material must be replicated before mitosis?
- cells are genetically identical and have the same DNA.
- so both daughter cells receive a full copy.
What are the defining features in Prophase under a microscope?
- chromosomes become visible
- there is no Nucleolus
- nuclear envelope is disappearing
Outline the events that occur during prophase..
- chromosomes condense, shorten and thicken so they are visible.
- nuclear envelope starts to disintegrate.
- Nucleolus has disappeared.
- centrioles replicate and migrate and spindle fibres start to form.
What is the defining feature in a cell in Metaphase under a microscope?
The chromosomes are aligned in the equator making it look dark
Outline the events that occur during Metaphase..
-chromosomes attach to the spindle fibres via the centromere-they align on the equator.
What are the defining features on a cell in Anaphase under the microscope?
- centromere has split.
- can see the sister chromatids being pulled apart to opposite poles of the cell.
Outline the events that occur during Anaphase..
- the centromere splits.
- sister chromatids are pulled apart to opposite poles of the cell.
What are the defining features of a cell in Telophase under the microscope?
-the chromatids are on two sides with nuclear envelopes around them.
Outline the events that occur during Telophase..
-nuclear envelopes reform around the chromatids at each pole.
What are the defining features of a cell in Cytokinesis?
- two deprecate new daughter cells have been formed.
- there is a line down the middle
Outline the events that occur during Cytokinesis..
- the cytoplasm splits into two.
- the cell membrane comes in and pinches off to form two new daughter cells.
- the chromatid unravels.
Suggest how cell division in plants differs from cell division in animals?
- In cytokinesis in animal cells, the two me daughter cells are made. No cell wall.
- In cytokinesis in Plant cells, they need to form a cell wall. They do not have centrioles. Cytokinesis starts in the centre of the cell. Only cells that complete this are the meristem and cambium.
What is the chromosome number in daughter cells in Meiosis and in Mitosis?
Meiosis= 23 chromosomes.
Mitosis = 46 chromosomes.
What number of divisions does Meiosis and Mitosis have?
Meiosis = 2 consecutive divisions.
Mitosis = 1 division.
What type of cells does Meiosis produce?
Haploid cells (n)
What type of cells does Mitosis produce?
Diploid cells (2n)
Does Meiosis produce genetically different or identical cells?
Genetically Different cells
Does Mitosis produce genetically different or identical cells?
Genetically Identical cells
How many cells does Meiosis produce?
4 cells (these are gametes needed for sexual production)
How many cells does Mitosis produce?
2 cells
Meiosis ….. The chromosome number?
Halves
Mitosis …… The chromosome number?
Maintains
Fertilisation ….. The chromosome number?
Doubles
Outline reproduction in yeast cells..
- the nucleus divides by Mitosis.
- the cell swells on one side(bulges).
- nucleus or organelles move into bud.
- bud pinches off and a cell wall is formed.
- bud becomes a separate copy.
