Cell Division, Diversity and Organisation Flashcards
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
How are Root Hair Cells specialised? (3)
- Hair like projections
- Greatly increase SA
- Root able to absorb more
water+minerals from soil
How are guard cells specialised? (4)
- Spiral thickenings of cellulose - When turgid, cell opens - When flaccid, stoma closes - Controlling passage of gases
Define ‘Tissue’
A group of similar, specialised, cells which collectively carry out a specific functions
Define ‘Organ’
A group of tissues working together to collectively carry out a specific function which has an effect on entire organism
Define ‘Organ System’
Collection of organs with related and interdependent functions eg. digestive system
Define Pluripotent stem cells
Stem cells that can develop into any cell type (including umbilical cord)
Define Omnipotent stem cells
Can develop into many types of cell
Define Multipotent stem cells
Can develop into limited/few cells
What is Cambium?
- Layer of meristem cells - Lies between Xylem and
Phloem - Divide to produce new
Xylem andPhloem
Where is Squamous epithelia found?
- Oral cavities
- Blood Vessels
- Alveoli of lungs
Where is Ciliated epithelium found?
- Trachea
- Fallopian tubes
How is Squamous epithelium adapted/specialised for its function?
- Some variants are thin and lubricated to enable efficient gas exchange
- Others reinforced with Keratin to improve resistance to friction
