1.2 Ultrastructure of cells

Question 1

Outline the structure of a prokaryote cells

Answer 1

• cell wall
• plasma membrane
• cytoplasm
• Pili
• Flagellum
• 70s Ribosomes
• Nucleoid region
• plasmids
• capsule

Question 2

Explain the different structure of prokaryote cell and draw the prokaryote cell

Answer 2

Pili - protein filaments ( cell adhesion ) and transfers DNA between two cells

Flagellum - movement of organism

70s Ribosomes - sites of protein synthesis

nucleoid region - controls all activities of cells

plasmids - small circles of DNA that carry a few genes

capsule - helps prokaryotes cling to each other and other surface, prevents the cell from dying out

Question 3

What process does prokaryote divide ?

Answer 3

reproduced by binary fission, reproduce asexually

Question 4

outline the structure of a eukaryote cell and draw the eukaryote cell

Answer 4

plasma membrane 
cytoplasm 
mitochondria 
80s ribosomes 
Nucleus 
Nucleolus 
Smooth and rough endoplasmic reticulum 
Golgi apparatus 
vesicle 
Lysosomes (absent from plant cells) 
Centrioles (absent from plant cells)
Vacuole (absent from animal cells)
cell wall (absent from animal cells) 
Chloroplasts (absent from animal cells)

Question 5

Explain the structure of the animal cells

Answer 5

Mitochondria - site of respiration, ATP generated

80s ribosomes - site of protein synthesis

Nucleus - controls all activities of the cell, and reproduction

Nucleolus - part of nucleus that produces ribosomes

SER - producing and storing lipids, including steroids

RER - transports and synthesises proteins

Golgi apparatus - processes and packages proteins, released in golgi vesicle

Vesicle - small sac that transports and release substance produced by the cell by fusing with cell membrane

Lysosomes - contain hydrolytic enzymes, destruction of microbes by engulfing white blood cells, destruction of old cellular organelles

Centrioles - used for nuclear division by helping to establish microtubules

Question 6

Explain the structure of a eukaryotic plant cell

Answer 6

cell wall - protects cell
maintains it shape
prevents from bursting in hypotonic media

chloroplasts - double membrane bound organelles
contain chlorophyll pigments
responsible for photosynthesis

Vacuole - helps osmotic balance
helps storage of substance
may have hydrolytic similar functions for
lysosomes

Question 7

define microscope resolution

Answer 7

the shortest distance between two points that can be distinguished

Question 8

Define magnification

Answer 8

the ability to make small objects seem larger, such as making a microscopic organism visible

Question 9

Differences between electron microscope and light microscope

Answer 9

electron microscope have a much higher resolution than light microscope

light microscope is useful for observing living
organisms in colour

electron microscope allows us to see the ultrastructure of cells

electron microscope can see viruses but light microscopes cant

Question 10

identify the main structure in both the eukaryotic and prokaryotic cell and explain their functions

Answer 10

cell wall - protects and maintain it shape, prevent cells from bursting in hypotonic media

plasma membrane - surrounds the cells control the movement of substances in and out of the cell

cytoplasm - medium that fits the cell, site of metabolic reactions

Question 11

differences between eukaryotic cell and prokaryotic cell

Answer 11

Eukaryote cells have a sperate membrane enclosed nucleus, DNA of prokaryotes float freely in the cytoplasm

Eukaryotic cells have membrane bounded organelles where prokaryotes don’t

Eukaryotic cells have a compartmentalized structure, cells divide into numerous enclosed regions

Question 12

What does arthropod and angiospermophyta

Answer 12

arthropod - animal

angiospermophyta - plants