1.2 Ultrastructure of cells

Question 1

PROKARYOTIC CELLS

They are the ……. organisms to evolve on earth and contains ribosomes ….s. They divide by ……. …….

Answer 1

They are the first organisms to evolve on earth and contains ribosomes 70s. They divide by binary fission

Question 2

Process of binary fission

Answer 2

• Bacterial chromosome is replicated
• Move to opposite sides of the cell
• Cell wall and plasma membrane are pulled inwards so that the cell pinches apart to form two identical cells (daughter cells)

Question 3

Cytoplasm, Nucleoid region, Cell wall, Plasma membrane. FUNCTIONS

Answer 3

Cytoplasm- Site for metabolic reactions. Enzymes contained
Nucleoid Region- Contains naked DNA which stores genetic information that controls the cell
Cell Wall- Prevents damage and bursting if internal pressure is too high
Plasma Membrane- Controls entry & exit of substance. Encloses cell content

Question 4

Pili, Ribosomes, Flagella. FUNCTIONS

Answer 4

Pili- Protein filaments used for cell to cell adhesion.
Ribosomes- Synthesize proteins by translating messenger RNA.
Flagella- propel cell form one area to another. Solid & inflexible.

Question 5

EUKARYOTIC CELLS

An organism whose cell contains a ……. and has ribosomes ..s. The cells are c…………

Answer 5

An organism whose cell contains a nucleus and has ribosomes 80s. The cells are compartmentalized.

Question 6

rER, Golgi apparatus, Lysosome. FUNCTIONS

Answer 6

rER- Synthesizes proteins to be secreted outside the cell
Golgi apparatus- For processing and packaging of proteins
Lysosome- high concentration of digestive enzymes used to breakdown ingested food, organelles or even whole cell (lytic)

Question 7

Nucleus, Mitochondrion, Chloroplasts. FUNCTIONS

All double membrane

Answer 7

Nucleus- Holds the chromosomes
Mitochondrion- Site of aerobic respirations
Chloroplasts- Photosynthesis occurs here