Cell structure and organisation 1.2 (organelles)

Question 1

What is the function of the cell membrane?

Answer 1

-separates cells from surrounding cells/tissue fluid
-Allows different proteins to control what enters/leaves cell
-Allows different processes to occur in different organelles
-7-10nm wide

Question 2

What is the function of the nucleus?

Answer 2

-Contains DNA (chromatin) which codes for proteins
-Site of DNA replication & transcription
-10-20µm

Question 3

What is the function of nuclear pores?

Answer 3

Allows mRNA and ribosomes to be transported out of nucleus

Question 4

What is the function of the nucleolus?

Answer 4

produces rRNA/tRNA & ribosomes

Question 5

What is the function of the nuclear envelope?

Answer 5

-Double membrane, outer membrane is continuous with endoplasmic reticulum
-Separates nucleus from surrounding cytoplasm

Question 6

What is the function of mitochondria?

Answer 6

Site of ATP production through aerobic respiration

Question 7

What are the structures within the mitochondria?

Answer 7

• 1-10µm long cylinders, longer surface area:volume ratio and reduced diffusion distance
  -Double membrane, inner membrane folds to form Cristae
  -Matrix contains enzymes, 70s ribosomes, circular DNA

Question 8

What is the function of Rough Endopasmic Reticulum?

Answer 8

-Flattened sacs called Cisternae, connected to nuclear envelope
-Transport & store proteins
-Produces vesicles which merge with golgi body
-Has ribosomes

Question 9

What is the function of Smooth Endoplasmic Reticulum?

Answer 9

-No ribosomes
-Synthesize, package & transports lipids and steroids

Question 10

What is the function of the golgi body/apparatus?

Answer 10

-Modifies & packages proteins into vesicles
-Produces glycoproteins, enzymes & lysosomes
-Transport & storage of some lipids

Question 11

What is the function of centrioles?

Answer 11

-Located just outside the nucleus
-2 hollow cylinders of microtubules at right angles to each other
-Forms the spindle during cell division (not present in higher plant cells)

Question 12

What is the function of lysosomes?

Answer 12

-Small temporary vacuoles, pinched off from golgi body
-Contains digestive (hydrolyctic) enzymes to break down worn out cells and organelles
-Involved in digestion during phagocytosis
-Involved in apoptosis (normal cell death)

Question 13

What is the function of the cellulose cell wall?

Answer 13

-High tensile strength, microfibril arrangement which helps plant cells become turgid
-Allows water and minerals to move across the route via apoplast pathway

Question 14

What is the function of chloroplast?

Answer 14

-Double membrane
-Liquid filled stroma containing starch grains, 70s ribosomes & circular DNA
-Stroma contains stacks of thylakoids called grana (thylakoid membranes)
-Increase surface area for chlorophyll pigments

Question 15

What is the function of the vacuole?

Answer 15

-Large permanent vacuole bound by the tonoplast
-Contains cell sap and solutes (glucose, amino acids & minerals)
-Becomes turgid due to osmosis so plays a major role in supporting plant tissue

Question 16

What is the function of plasmodesmata?

Answer 16

-Connects plant cells together
-Allows water to move between cells via symplast pathway