L6 - basic biogenetics and overview of cellular metabolism

Question 1

Metabolism

Answer 1

Describes all chemical reactions that take place in the cells of the body

Question 2

Catabolic &; Anabolic pathways

Answer 2

Catabolic - breaking down molecules to create energy

Anabolic - building up molecules using energy ( from catabolic reactions )

Question 3

If free energy or delta G is neg- …

Answer 3

A reaction will start SPONTANEOUSLY

ie reaction is FAVOURABLE

Question 4

Hydrolysis of ATP

Answer 4

ATP & H20 ——–ADP & Pi

• Very energetically favourably
• Thus it is used to drive energetically UNFAVOURABKE reactions

Question 5

How is ATP made??

Answer 5

• Made using energy from FOOD molecules like Carbohydrates , fats & AA.
• food molecules release energy by oxidation
• then we get ATP!

Question 6

Recap of all OXI & RED definitions

Answer 6

OXIDATION :
Loss of electrons
Loss of hydrogen
Gain of 02

RÉDUCTION :
Gain of electrons
Gain of hydrogen
Loss of 02

Question 7

Reasons why ATP might be hydrolysed to ADP:

Answer 7

• Active transport (remember?? In receptor tyrosine kinase?? ENZYME COUPLED RECEPTOR )
  Biosynthesis - making proteins

Question 8

co factors

• aka?
• what are they and what do they do ?

Answer 8

CO enzymes : & electron carriers
- Non protein molecules that work with an enzyme to initiate or aid the function of the enzyme
- they bind to the enzyme
????

Question 9

Oxidation of food molecules

Answer 9

• ie break down of GLUCOSE
• ( stored as glycogen in the liver and muscles )
• this reaction is vvvvv favourable -2879 kJ/mol!!
• thus it has to take place in Steps - électron carriers or co enzymes do this

Enzymes lower AE remember!!

Question 10

Eg of 2 electron carriers or co- enzymes

Answer 10

NaDH

FaDH2

Question 11

Activated carriers aka?

Eg’s

Answer 11

Co enzymes
Co factors
Biological molecules that can STORE energy by accepting some sort of chemical group

Activated carrier : ATP
Group it carries : phosphoryl

AC: FaDH2 , NaDH
What it carries? Electrons
Summary AC can store energy and transfer chemical groups

Question 12

How does NAD+ become NADH ?

Answer 12

Accepts 2 e- & 1 proton

Question 13

FaD to FaDH2?

Answer 13

Accepts 2 p & 2 e-

Covalently linked to the enzyme for which it acts as a co- enzyme

Question 14

Coenzyme A is ?

Answer 14

AC: Activated Carrier

- Carries Acyl group

Question 15

Metabolism of glucose : stages

this is done much better in CBL notes

Answer 15

1. Glycolysis - breaking down of glucose to pyruvate
   - glucose (6C) —— x2 pyruvate ( 3C & 3C) &; 2ATP & 2NaDH

• In aerobic conditions, pyruvate enters mitochondria matrix & is converted to Acetyl CoA.
• has to Lose 1 carbon - 3C -2C
• C02 needs one

2. Crebs cycle / Citric acid cycle / TCA cycle
   - result:
   3NaDH
   2 C02
   1 ATP
   1FaDH2
3. OXIDATIVE PHOSPHORYLATION
   - e- from NaDH & FaDH2 are passed to 02, forming H20
   - energy released is used to pump H+ ions or protons out of matrix
   - H+ flows back down it’s CG
   & generates ATP from ADP

Question 16

Control or regulation of anabolic and catabolic pathways

Answer 16

• usually regulated reciprocally to avoid futile cycling
• CATABOLIC - occurs if ATP is low & more is needed
• ANABOLIC - occurs if ATP is high & needs to be used up

Question 17

There are key control points in metabolic pathways. But what can we do to change activity of a particular reaction or enzyme if necessary??

Answer 17

SHORT term :

• Binding of allosteric inhibitors or activators to alter enzyme activity ( ability to switch it on or off)
• post translation modification like phosphorylation

LONG Term :
Changes in gene expression & proteolysis ( breaking down of proteins )
Both alter the no. If enzyme,es

Note : hormones can have bother short and long term affects on metabolic regulation

Question 18

Most ATP made where and how

Answer 18

In mitochondria

By oxidative phosphorylation

Question 19

electron carriers

Answer 19

• carry and transfer electrons along electron transfer chain
• thus ; they are involved in oxidation and reduction reactions