structure of cells/viruses

Question 1

Describe the structure and function of the Nucleus [4]

Answer 1

Nuclear envelope

Nuclear pores > allow substances to move between the nucleus and cytoplasm (e.g. mRNA)

Nucleolus > Nucleolus makes ribosomes

DNA / chromatin > Controls the cells activity though transcription of mRNA

Question 2

Describe the structure and function of Mitochondria [3]

Answer 2

Double membrane > controls the substances moving in and out of the organelle

Crista > folded structure, increasing surface area, so more respiration can take place

Matrix > where chemical reactions take place

Question 3

Describe the structure and function of Chloroplasts [4]

Answer 3

Double membrane > controls the substances moving in and out of the organelle

Thylakoid > membranes are stacked up in some parts to form granum, increasing surface area, so more photosynthesis can take place

Stroma > where chemical reactions take place

Chlorophyll > absorbs light for photosynthesis

Question 4

Describe the structure and function of the Golgi Apparatus [5]

Answer 4

3 or more fluid filled membrane bound sacs with vesicles at edge

• Receives protein from rough endoplasmic reticulum
• Modifies protein
• Packages into vesicles for transport to cell surface membrane for exocytosis
• Also makes lysosomes

Question 5

Describe the structure and function of Lysosomes [2]

Answer 5

membrane bound sphere

hydrolytic enzymes which break down pathogens or worn out cell components

Question 6

Describe the structure and function of Ribosomes [4]

Answer 6

Made from 1 large and 1 small subunit
Float free in cytoplasm or bound to rER
Not membrane bound

Site of protein synthesis via translation

Question 7

Describe the structure and function of the rough endoplasmic reticulum [3]

Answer 7

Ribosomes bound by a system of membranes

Folds polypeptides to secondary / tertiary structure
Packages into vesicles for transport to the Golgi apparatus

Question 8

Describe the structure and function of the smooth endoplasmic reticulum

Answer 8

system of membranes

Synthesises and processes lipids

Question 9

Describe the structure and function of the Cell Wall [2]

Answer 9

Made mainly of cellulose in plants and algae (chitin in fungi)

Rigid structure surrounding cells in plants, prevents the cell from changing shape and bursting

Question 10

Describe the structure and function of the Vacuole [3]

Answer 10

Membrane containing cell sap (weak solution of sugars/salts)

• Maintains pressure in the cell
• Stores/isolates unwanted chemicals in the cell

Question 11

Describe the organisation of specialised cells in complex multicellular organisms [4]

Answer 11

Specialised cell > basic subunit in all living organisms;
specialised for a particular function

Tissue > Group of organised specialised cells; working together to perform a particular function

Organ > Group of organised different tissues; working together to perform a particular function

Organ System > Group of organised organs; working together to perform a particular function

Question 12

Give 4 differences between Prokaryotic and Eukaryotic Cells

Answer 12

Prokaryotic cell cytoplasm contains no membrane bound organelles (e.g. mitochondria)
WHEREAS
Eukaryotic cell contains membrane bound organelles

Prokaryotic cell has no nucleus / contains free floating DNA
WHEREAS
Eukaryotic cell has a nucleus containing DNA

Prokaryotic DNA is circular and isn’t associated with proteins called histones
WHEREAS
Eukaryotic DNA is linear and is associated with proteins called histones

Prokaryotic cells may have…
- one or more plasmid
- a capsule
- one or more flagella
WHEREAS
Eukaryotic Cells do not

Question 13

Give 2 factors of a Virus

Answer 13

Acellular → not made of or able to be divided into cells
Non-living → unable to exist/reproduce without a host cell