Mitochondria And Ribosomes

Question 1

What is the difference between the cytosol and cytoplasm?

Answer 1

Cytoplasm is all material bar nucleus enclosed by cell membrane
Cytosol is the aq portion of the cytoplasm

Question 2

Describe the structure of the mitochondria

Eg. membrane, mobility, associations

Answer 2

Mitochondria have a double membrane
Mobile organisms that change shape and position
Associate with multiple microtubules of cytoskeleton demines orientation and distribution

Question 3

What is the outer mitochondria membrane permeable to ?

Answer 3

5KDa or less molecules and ions

Question 4

Name 6 parts of the mitochondria structure

Answer 4

Outer membrane
Inner membrane
Intermembrane Space
Electron Transport Chain
Matrix
Mitochondrial DNA

Question 5

What does the inner membrane contain?

Answer 5

Contains Cristae containing proteins for ETC
Selected ions, protons and phosphates can pass via transport proteins
Others pass via diffusion barrier

Question 6

What are the 2 types of mitochondrial fission and how do they differ?

Answer 6

Midzone fission- division to replicate

Peripheral Fission =get rid of damaged material

Question 7

Describe Stage 1 of chemiosmosic coupling

Answer 7

High Energy electrons (derived from oxidation of food)
are transferred along a series of electron carriers in the membrane
The transfers release energy which is used to pump H+ across membrane
This creates a protein gradient and involves 4 protein complexes
At the end 2 electrons reduce oxygen to H2O

Question 8

Describe Stage 2 of chemiosmotic coupling

Answer 8

Proton gradient provides energy store to drive ATP synthase
ADP +Pi- ATP
Carbs and fats are broken down releasing high energy electrons
2 electrons picked up by NAD+ creating NADH
this carries electrons to inner mitochondrial membrane
Glycolysis converts glucose to pyruvate
In mitochondria pryruvate is oxidised by O2 producing CO2 and H2O plus 15 atp molecules

Question 9

In mitochondria what oxidises pyruvate and what are the products?

Answer 9

In mitochondria pryruvate is oxidised by O2 producing CO2 and H2O plus 15 atp molecules

Question 10

What is mtDNA or mDNA

Answer 10

Mitochondrial DNA

Question 11

How many bases in mDNA in humans

How many proteins does this code for?

Answer 11

1659 bases

Encodes 13 proteins

Question 12

Why is mDNA uses in phylogenetic studies?

Answer 12

It evolves faster than human DNA

Question 13

mDNA is mostly inherited from the mother or the father?

Answer 13

Mother

Question 14

What is the size and subunits of the Prokaryotic ribosome?

Answer 14

70S

50S large subunit and 30S small subunit

Question 15

What is the size and subunits of the Eukaryotic ribosome?

Answer 15

80S
60S large subunit
40S small subunit

Question 16

What does the S stand for in relation to the subunits?

Answer 16

S=Svedberg units
Rate of precipitation when centrifuged
hence the larger the subunit the faster it precipitates

Question 17

Name the 3 binding sites on a ribosome and what occurs at which?

Answer 17

mRNA binding site
A-site binding of aminoacyl tRNA
P-site binding of the most recent amino acid
E-site/exit site of deacylated tRNA

Question 18

Where is the A-site P-site and E-site?

Answer 18

On the ribosomes large subunit

Question 19

Where is the mRNA binding site?

Answer 19

On the ribosomes small subunit

Question 20

What does RIP stand for?

Answer 20

Ribosomes Inactivating Proteins

Question 21

What are the 2 types of RIP and how do they differ?

Answer 21

Type I cannot cross the cell membrane and not cytotoxic

Type II has a binding domain allows entry of the toxin into the cells crossing the plasma membrane