TOPIC 3: Voice of the Genome Flashcards
What is the role of the nucleus?
contains genetic info as chromatin
What is the structure of the nucleus?
double membrane
nucleolus
nuclear pores
What is the nucleolus?
dense area where ribosomes are made
What is chromatin?
DNA wrapped around histones
Describe the structure of mitochondria.
double membrane
inner membrane folded into cristae (large SA/V for respiration)
What is the role of the centrosome?
forms mitotic spindle & cytoskeleton
Describe the structure of centrosome.
2 centrioles = 1 centrosome
What is the role of smooth ER?
synthesis of lipids & hormones
What is the role of rough ER?
synthesis of membrane bound or secreted proteins
How do you differentiate between rER and sER?
rER has ribosomes
What is the role of the golgi?
modification and packaging of proteins
What are vesicles?
small membrane-bound sacs for storage and transport of molecules
What is the role of the lysosome?
break down of material in cell
What is the structure of the lysosome?
single membrane with digestive enzymes inside
What is the role of the cytoskeleton?
gives the cell structure and allows it to change shape
What is the secretory pathway?
- Proteins synthesised on rER (+ folded to form tertiary structure and modified, glycosylation)
- Proteins packaged into vesicles and transported to Golgi
- Vesicles fuse with Golgi, where protein is modified further
- Protein packed into secretory vesicles and pinch off to the cell surface membrane
- Vesicles fuse with cell membrane and exit by exocytosis/transmembrane protein
Which organelles can be found in prokaryotes?
circular DNA, cell wall, capsule, food granules, flagellum, pili, plasmid and mesosome
What is the prokaryotic cell wall made of?
peptidoglycan
What is the role of the slime capsule?
protection & prevention of dehydration
What are the food granules?
glycogen & lipids
DIfferences between prokaryotes and eukaryotes
prokaryotes don’t have nuclei (circular DNA)
eukaryotes have membrane-bound organelles
What does the mitochondria in sperm cells do?
tightly packed
provides ATP for tail movement
What does the flagellum do?
propels the sperm
What do microtubules do?
keep sperm in suspension for movement
What is the role of the acrosome?
storage for enzymes which digest the zona pellucida
What is the role of follicle cells?
surround ovum and release chemicals to trigger acrosome reaction
What is the role of the zona pellucida?
glycoprotein layer needed for binding of sperm
What is the role of the cortical granules?
lysosome which releases enzymes to thicken zona pellucida and prevent further entry of sperm
What are the lipid droplets?
food store for embryo
Describe the stages of fertilisation
- Follicle cell releases chemical which triggers acrosome reaction
- Acrosome membrane fuses with front of sperm cell membrane and digestive enzymes released
- Enzymes digest zona pellucida
- Sperm membrane fuses with ovum membrane & nucleus enters ovum
- Cortical reaction: zona pellucida thickens to prevent entry of other sperm
- Egg and sperm nuclei fuse - diploid zygote
What is the gene locus?
location of genes on a chromosome
What is gene linkage?
when genes are located on the same chromosome and aren’t inherited independently
