Cell Division, Diversity and Organisation Flashcards
(36 cards)
Name 4 things that happen in ‘S’ phase
- Synthesis of new DNA
- DNA replication begins,
- Chromosomes replicate
- Occurs very quickly
Name 3 things that happen in G2 phase?
- Cell growth continues
- Enzymes check DNA
- (Check if they’ve been
replicated properly)
Name 3 things that happen in the G1 phase?
- Growth
- Chromosomes still
chromatin - Amino acids used to
form millions of proteins
What does the G2 checkpoint check for?
Checks for cell size and DNA replication
What does the M checkpoint check for?
Checks chromosomes appropriately attached to spindle
What does the G1 checkpoint check for?
Checks:
- Cell size
- Nutrient availability
- Growth factor availability
- Confirms intact DNA
Name the 4 things that happen in Interphase
- DNA replication
- Organelle doubling
- Proteins made
- Cell checks for mutation
6 things happen in Prophase, what are they?
- Chromosomes and Replicated chromosomes supercoil
- Nuclear envelope breaks down
- Centrioles divide into 2
- Move to opposite cell ends
- Spindle forms
- Nuclear membrane breaks down
What 3 things happen in Metaphase?
- Replicated chromosomes line up in middle of the cell
- Move to central region of spindle
- Each joins spindle thread by centromere
What 5 things happen in Anaphase?
- Replicas of each chromosome pulled apart to opposite ends of the cell
- Sister chromatids separate
- Becoming individual ones
- Spindle fibers shorten
- pulling sister chromatids away from each other
What 5 things happen in Telophase?
- 2 nuclei formed
- Sister chromatids reach
opposite poles of the cell - Nuclear envelopes reform
- Spindle breaks down
- Chromosomes uncoil
What 4 things in life cycles are mitosis significant for?
- Asexual reproduction
- Growth, identical new cell
- Repair, damaged cells
- Replacement, RBC’s
Give 4 things that make Meiosis important in life cycles?
- Takes place in sex organs
- Gametes produced here
- Important to have
genetically different
gametes - Promoting genetic
variation and allows
natural selection
What is Recombination?
Chromatids swapping genes between themselves, ensuring 4 daughter cells aren’t identical
What 4 things happen in Prophase II?
- Chromosomes pair up
- Nuclear membrane breaks
down - Centrioles divide in 2
- Pair of sister chromatids visible ( light microscope )
What 4 things happen in Metaphase II?
- Replicated chromosomes line up down middle of cell - Centrioles move to opposite poles of the cell, forming spindle - Chromosomes move to central region of spindle - Each joins to spindle thread by its centromere
What 5 things happen in Anaphase II?
- Sister chromosomes pulled apart to poles of cell - Sister chromatids separated as centromere splits becoming individual chromosomes - Each one genetically unique - Spindle fibers shorten - pulling sister chromatids away from each other
What 3 things happen in Telophase II?
- New nuclear envelope forms around each chromatid - Spindle breaks down and disappears - Chromatids uncoil
What happens in Cytokinesis II?
Cytoplasm and surface membrane divide, creating 4 haploid daughter cells
How are Erythrocytes specialised? (4)
- Has no organelles
- Bi-concave shape
- Maximises oxygen
carrying capacity - Maximises space for
haemoglobin
How are Neutrophils specialised? (3)
- Lobed nucleus
- Granular cytoplasm, lots
of lysosomes - Potent enzymes in
lysosomes specialised to
kill microorganisms
How are Epithelial cells specialised? (2)
- Cover internal/external
surfaces - 2 types squamous/ciliated
How are sperm cells specialised? (5)
- Many mitochondria make energy for movement - head contains specialised lysosomes to break egg - Small, long and thin - Tail propels sperm - Diploid for Gamete role
How are Palisade cells specialised?
- Long shape maximises light absorption - Contains lots of Chlorophyll - Specialised for photosynthesis
