3. Voice of the genome
3.a Cells
Cell structure
Ultrastructure of eukaryotic cells
● Nucleus
- Surrounded by double membrane (envelope)
- Envelope contains pores
- Contains dna
- Contains nucleolus which is site of ribosome production
● Rough endoplasmic reticulum
- Membrane bound sacs
- Ribosomes on surface
- Folds and processes proteins
● Smooth endoplasmic reticulum
- Membrane bound sacs
- Produces and processes lipids
● Golgi apparatus
- Fluid filled sacs
- Vesicles surrounding edges
- Modifies and packages proteins (and lipids)
- Produces lysosomes
● Golgi vesicles
- Transport substances through cell membrane
● Mitochondria
- Double membrane
- Inner membrane is folded to form a cristae
- Contains enzymes needed for cellular respiration
● Centrioles
- Hollow cylinders
- Involved in cell division
● 80s ribosomes
- Two subunits
- Site of protein synthesis
● Lysosomes
- Vesicles
- Contain digestive enzymes
- Single membrane
Ultrastructure of prokaryotic cells
● Cell wall
- Rigid outer layer
- Made of peptidoglycan
- Provides strength and support
, 3. Voice of the genome
● Slime capsule
- Protective layer
- Helps cell retain moisture and adhere to surfaces
● Plasmid
- Circular dna
● Flagellum
- Tail-like structure
- Rotates to move cell
● Pili
- Hair-like structures
- Attach to other bacterial cells
- Allow exchange of plasmids
● 70s ribosomes
- Two subunits
- Site of protein synthesis
● Mesosomes
- Infoldings of inner membrane
- Artefact/contain enzymes for respiration
Protein trafficking
The production of proteins
● Proteins are produced in the ribosomes on the Rough Endoplasmic Reticulum
● They are then folded and processed in the ReR
● Transported from the ReR to the Golgi Apparatus via transport vesicles
● Then modified in the Golgi Apparatus and packed into Golgi vesicles/secretory
vesicles
● Vesicles take protein to cell membrane where it fuses and releases the protein via
exocytosis
Eukaryotic cell cycle
1. Interphase
1. G1 →cell grows, dna replicates
2. S →chromosomes replicated, condense to form
chromatids
3. G2 → cell prepares to divide, replicates organelles
2. Mitosis
4. PROPHASE → nuclear membrane breaks down,
chromosomes condense
5. METAPHASE → chromosomes line up at equator
6. ANAPHASE → pulled apart by spindle fibres from
centrioles
7. TELOPHASE → new membranes form
3.a Cells
Cell structure
Ultrastructure of eukaryotic cells
● Nucleus
- Surrounded by double membrane (envelope)
- Envelope contains pores
- Contains dna
- Contains nucleolus which is site of ribosome production
● Rough endoplasmic reticulum
- Membrane bound sacs
- Ribosomes on surface
- Folds and processes proteins
● Smooth endoplasmic reticulum
- Membrane bound sacs
- Produces and processes lipids
● Golgi apparatus
- Fluid filled sacs
- Vesicles surrounding edges
- Modifies and packages proteins (and lipids)
- Produces lysosomes
● Golgi vesicles
- Transport substances through cell membrane
● Mitochondria
- Double membrane
- Inner membrane is folded to form a cristae
- Contains enzymes needed for cellular respiration
● Centrioles
- Hollow cylinders
- Involved in cell division
● 80s ribosomes
- Two subunits
- Site of protein synthesis
● Lysosomes
- Vesicles
- Contain digestive enzymes
- Single membrane
Ultrastructure of prokaryotic cells
● Cell wall
- Rigid outer layer
- Made of peptidoglycan
- Provides strength and support
, 3. Voice of the genome
● Slime capsule
- Protective layer
- Helps cell retain moisture and adhere to surfaces
● Plasmid
- Circular dna
● Flagellum
- Tail-like structure
- Rotates to move cell
● Pili
- Hair-like structures
- Attach to other bacterial cells
- Allow exchange of plasmids
● 70s ribosomes
- Two subunits
- Site of protein synthesis
● Mesosomes
- Infoldings of inner membrane
- Artefact/contain enzymes for respiration
Protein trafficking
The production of proteins
● Proteins are produced in the ribosomes on the Rough Endoplasmic Reticulum
● They are then folded and processed in the ReR
● Transported from the ReR to the Golgi Apparatus via transport vesicles
● Then modified in the Golgi Apparatus and packed into Golgi vesicles/secretory
vesicles
● Vesicles take protein to cell membrane where it fuses and releases the protein via
exocytosis
Eukaryotic cell cycle
1. Interphase
1. G1 →cell grows, dna replicates
2. S →chromosomes replicated, condense to form
chromatids
3. G2 → cell prepares to divide, replicates organelles
2. Mitosis
4. PROPHASE → nuclear membrane breaks down,
chromosomes condense
5. METAPHASE → chromosomes line up at equator
6. ANAPHASE → pulled apart by spindle fibres from
centrioles
7. TELOPHASE → new membranes form
