Cell organelles, structure and function

Question 1

Describe the structure and function of the nucleus:

Answer 1

Structure= Nuclear envelope, Nuclear pores, Nucleoplasm, Chromosomes, Nucleolus (smaller sphere inside which is site of rRNA and makes ribosomes)

Function= Site of DNA replication and transcription, contains genetic code

Question 2

Describe structure and function of the Endoplasmic reticulum:

Answer 2

Structure= folded membranes called cisternae, rough have ribosomes on cisternae

Function= RER- protein synthesis, SER- Synthesis and store of lipids and carbohydrates

Question 3

Golgi apparatus and vesicles structure and function:

Answer 3

Structure= cisternae, secretary vesicles pinch off from cisternae

function= add carbohydrates to proteins to form glycoproteins,
produce secretory enzymes,
secrete carbohydrates,
transport modify and store lipids, form lysosomes,
products are transported to cell surface in golgi vesicles where they fuse with the membrane and the contents is released.

Question 4

Describe the function and structure of Lysosomes:

Answer 4

Structure= bags of digestive enzymes

Function= Hydrolyse cells,
completely break down dead cells (autolysis),
Exocytosis- release enzymes to outside of cell to destroy material,
Digest worn out organelles for reuse of materials

Question 5

Describe the structure and function of mitochondria:

Answer 5

Structure= Double membrane, inner membrane called cristae, fluid within the centre called mitochondrial matrix, loop of mitochondria DNA

Function= Aerobic respiration,
Site of ATP production,
DNA to code for enzymes needed in respiration.

Question 6

Describe the structure and function of Ribosomes:

Answer 6

Structure= 80s- eukaryotic cells, 70s- prokaryotic cells

function= protein synthesis

Question 7

Structure and function of the Vacuole:

Answer 7

Structure= Filled with fluid surrounded by a single membrane called a tonoplast

Function= Make cells turgid and provides support,
temporary store of sugars and amino acids,
The pigments may colour petals to attract pollinators.

Question 8

Describe the structure and function of a chloroplast:

Answer 8

Structure= surrounded by a double membrane, contains thylakoids, fluid filled stroma contains enzymes for photosynthesis.

Function= Site of photosynthesis

Question 9

Describe the structure and function of the Cell wall:

Answer 9

Structure= Plants- made of microfibrils of the cellulose polymer, Fungi- made of chitin

Function= provides structural strength to the cell

Question 10

Describe the structure and function of the cell membrane:

Answer 10

Structure= Phospholipid bilayer- molecules embed within and attached on the outside (proteins, carbohydrates, cholesterol)

Function= Controls the entrance and exit of molecules

Question 11

Differences in prokaryotic and eukaryotic cells:

Answer 11

Prokaryotic-
cells are much smaller
no membrane bound organelles
smaller ribosomes
no nucleus
may contain (plasmids, a capsule around the cell, flagella)

Question 12

What are plasmids?

Answer 12

Small loops of DNA which only carry a few genes, e.g antibiotic resistants genes (prokaryotic)

Question 13

What is the function of the capsule?

Answer 13

Slimy layer made of protein,
Prevents the bacteria from desiccating and protects the bacteria against the hosts immune system