A2.2 Cell Structure

Question 1

Outline cell theory

Answer 1

1. All living things are composed of cells.
2. All cells come from preexisting cells.
3. Cells are the basic unit of life.

Question 2

Features of a prokaryote

Answer 2

• Plasma membrane
• Nucleoid
• Cytoplasm
• 70S ribosomes
• Plasmid
• Cell wall
• Pili
• Capsule
• Flagellum

Question 3

Features of a eukaryote

Answer 3

• Plasma membrane, nucleus, cytoplasm
• Cell wall (cellulose in plants, chitin in fungi)
• Rough ER
• Chloroplast
• Golgi apparatus
• Vacuole
• Lysosome
• 80S Ribosomes
• Mitochondria
• Secretory vesicle
• Smooth ER

Question 4

Differentiate prokaryotes from eukaryotes

Answer 4

• Prokaryotes reproduce through binary fission, eukaryotes through meiosis and mitosis.
• Prokaryotes has 70S ribosomes, eukaryotes have 80S ribosomes.
• Eukaryotes are compartmentalized, prokaryotes are not.
• Prokaryotes has a nucleoid, eukaryotes have a nucleus.

Question 5

Atypical cell structures

Answer 5

• Striated muscle fibres (multiple nuclei)
• Aseptate hyphae (no septa)
• RBC (no nucleus or mitochondria)
• Phloem (no nucleus and has sieve tubes)

Question 6

What do all typical cells have?

Answer 6

• DNA containing genetic material
• Cytoplasm that is mainly composed of water
• Plasma membrane

Question 7

What is the function of the cell wall?

Answer 7

Support the cell from increased or decreased turgor pressure in photosynthetic cells

Question 8

Function of the rough ER

Answer 8

Most ribosomes are attached here, synthesizing secretory proteins which are then packaged into transport vesicles

Question 9

Function of chloroplasts

Answer 9

Uses water, CO2 and light energy to produce glucose and oxygen for photosynthesis

Question 10

Function of Golgi apparatus

Answer 10

• Receives transport vesicles and modifies the proteins from the rER.
• Produces secretory vesicles.

Question 11

Function of vacuole

Answer 11

• Temporary and small in animal cells, storing glycogen in the liver and muscles
• Permanent and large in plant cells, storing starch in sinks, roots and leaves

Question 12

Function of lysosome

Answer 12

Sacs containing digestive enzymes that digest food and break down worn-out cell parts

Question 13

Function of 80S ribosomes

Answer 13

• Site of protein synthesis.
• Attached to rER used outside the cell or are freely suspended in cytoplasm used inside the cell.

Question 14

Function of mitochondria

Answer 14

Site of aerobic respiration, produces energy in the form of ATP from glucose

Question 15

Function of secretory vesicle

Answer 15

Sac carrying proteins from the Golgi apparatus to the cell membrane for secretion

Question 16

Function of smooth ER

Answer 16

Synthesizes lipids and buds off to form transport vesicles.

Question 17

Function of plasma membrane

Answer 17

Regulates what goes in and out of the cell

Question 18

What is the nucleoid?

Answer 18

Uncompartmentalized DNA not wrapped in a membrane, “naked” (not wrapped around a histone)

Question 19

Function of cytoplasm

Answer 19

The site of metabolic recations

Question 20

Function of 70S ribosomes

Answer 20

synthesizes proteins

Question 21

What is the plasmid?

Answer 21

circular DNA

Question 22

Function of pili

Answer 22

Adhering to surfaces and harpoons DNA to the environment

Question 23

Function of capsule

Answer 23

Prevents dehydration and adheres to surfaces

Question 24

Function of flagellum

Answer 24

locomotion, propels the cell

Question 25

What is magnification?

Answer 25

• How much larger an object appears compared to its real size
• Formula = image size / actual size