Topic 3 - Voice of the Genome Flashcards
What Is Meiosis?
The cell division of gametes, producing genetic variety
How Many Chromosomes Does Each Gamete Contain?
23
What Are the Stages of Interphase?
- Cell organelles are synthesised
- DNA replication
- Enough components to make 2 new cells
What Are the Stages of Prophase?
- Chromosomes condense into 2 chromatids, joined at the centromere
- Spindle is formed
- Centrioles act as poles either side of spindle
- Spindle fibres form off poles
- Nuclear envelope breaks down
What Are the Stages of Metaphase?
Centromeres attach to spindle fibres at the ‘equator’
What Are the Stages of Anaphase?
- Spindle fibres shorten and pull chromatids towards poles
- Centromeres split
- Spindle breaks down
What Are the Stages of Telophase?
- Chromosomes unravel into 2 separate nuclei
- Nuclear envelope reforms
What Are the Stages of Cytoplasmic Division?
A ring of protein filaments attach to the inside of cell surface membrane and contract until 2 new cells form
How Is Genetic Variety Achieved In Meiosis?
Independent assortment and crossing over
What Is Independent Assortment?
1 chromosome from each pair ends up in each gamete and the daughter cells form random assortments
What Happens In Crossing Over?
Homogolous pairs join and exchange sections of DNA
What Is Chiasma?
The site of crossing over
What Is A Nucleolus?
Where ribosomes are made
What Is A Lysosome?
Sacs containing digestive enzymes to break down substances and destroy cells
What Is A Smooth Endoplasmic Reticulum?
Makes lipids and steroids (e.g. hormones)
What Is A Mitochondrion?
- Site of aerobic respiration
- Forms cristae (mitochondria inner-foldings)
What Are Ribosomes?
- Made up of RNA and protein
- Site of protein synthesis
What Is The Golgi Apparatus?
- Flattened sacs formed by the fusion of vesicles.
- Modifies and packages proteins
What Is The Rough Endoplasmic Reticulum?
- Membrane bound sacs connected
- Ribosomes on surface for proteins to be made and transported
What Are Centrioles?
A ring of protein microtubules arranged in a helix to help form the spindle in meiosis
What Is The Cell Surface Membrane?
A phospholipid bilayer that forms a partially permeable barrier
