Kidneys have: - Decreased function - Smaller size - High urine protein

Biochemistry Flashcards by Anthony Tam

When was insulin discovered

1921

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what organ maintains blood glucose levels (BGL)

Pancreas

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Glucagon function, structure, where is it produced

29 a.a ppt

a-cells produce glucagon in response to low BGL

INCREASES BGL:
- glycogen breakdown to glucose

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What is the breakdown of glycogen to glucose called?

Glycogenolysis

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Insulin function and structure, where is it produced?

51 a.a ppt

B-cells produce insulin in response to high BGL

DECREASES BGL:
- stimulates all body cells (except brain cells) to take up glucose and stores it as glycogen

Stimulate glycogen synthesis

Promote storage of fuel e.g glucose, muscle growth, fat

generally anabolic - needs ATP

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What is the synthesis of new glucose called?

Gluconeogenesis

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where is GLUT2 found? what is its property

Pancreas B-cells, liver and gut

High Km (low affinity) glucose enters when conc. is high

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How does pancreatic islet B-cells sense glucose

Glucose floods in against conc. by AT

Moves into mitochondria, produces ATP

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Where does ATP produced by mitochondria go

ATP binds to K+ channel

depolarises cell

Promotes movement insulin containing vesicles to membrane surface, then secreted into blood

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What two things stimulate insulin secretion

Arginine and glucose

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Hyperglycaemic

excess glucose in blood, appears in urine

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Nephropathy

Kidneys have:

Decreased function
Smaller size
High urine protein

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Retinopathy

Elevated glucose results in uncontrolled uptake in some cells (epithelial cells of blood vessels)

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Gangrene amputation

Tissue death due to lack of blood supply

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Type 1 Diabetes

Autoimmune

Insulin dependent

Can be caused by viral infections causing loss of B-cells

Loss of insulin production

Inject insulin for treatment

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Type 2 Diabetes

Non-insulin dependent, common in older, obesity and stress

Target cells decreasing response to insulin

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Describe how glucose stays in blood in relation to mitochondria in pancreas

Too much glucose in blood
Too few mitochondria and overload

Mitochondria send free radicals to protect cell by decreasing GLUT

Thus blood glucose rises

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How to treat Type 2 DM

High intensity exercise

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Ketone bodies

Ketone bodies and glucose are the brain’s fuel

made in liver, exported in blood to brain

Diabetics and starving people smell like Acetone (nail polish removal)

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How is Acetone produced from fat

Fat metabolised by mitochondria forming Acetyl-CoA

Then rearrange to form acetone

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What causes ketoacidosis? (decrease in blood pH)

Acetoacetate

B-hydroxybutyrate

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In what kind of people does ketoacidosis occur

Untreated Type 1 diabetics

alcoholics

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Necrosis

Cells die when ATP stores decrease

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Creatine Kinase

Takes ADP adds a phosphate group from creatine phosphate and produces ATP

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Liver glycogen delivery

SLOW

What has the most stored ATP in body

Adipose fat

Why use Anaerobic pathways

FAST Creatine Phosphate and glycogen are self-contained within cells Oxygen dependent pathways dependent on transport of oxygen, this takes time, organ coordination and many reactions

Adrenalin function in breakdown

Stimulates breakdown glycogen --> glucose-1-phosphate --> glucose 6-phosphate

What does the oxidation of glucose 6-phosphate produce

ATP via glycolytic pathway

What is the major fuel for muscles in prolonged exercise

Fatty acids

Hyrdocyanic acid (cyanide) poisons what complex in ETC

Complex 4

Where does photosynthesis occur in plants? equation? what is oxidised and reduced?

Chloroplast 6CO2 + 6H2O --> (light) glucose + O2 CO2 reduced H2O oxidised

Chromophores

Pigments that contain absorb visible light Chlorophyll a and b

Photosystem 1

waves

Thylakoid membrane is impermeable to most ions and molecules EXCEPT what?

Mg and Cl-

What rate to photosystems acquire electrons at?

100 photons/sec

Quantum tunnelling

Flow of electrons through chloroplast

What is the function of the Manganese (Mn) ions in PS2

there are 4 Mn ions that rip water apart, taking theres e-

PS2 | what occurs

absorbs light @ 680nm light hits, electron excited passes energy then transferred to cytochrome complex gives up protons to thylakoid space

PS1

absrobs light @ 700nm excites electron, travels down ETC NADP reductase reduces NADP+ + H+ --> NADPH NADPH removes 2H+ from stroma

Non-cyclic phosphorylation

Production of ATP using electron flow from PS2 to PS1

Light reactions - what they produce - what they drive

Produce NADPH and ATP which are used to drive Calvin Cycle

Cytochrome complex

Transfers 4H+, these then drive ATP synthesis same way as in the mitochondria

Q-cycle

Deals w/ single electrons and transfers H+

How is proton gradient developed by:

Splitting of water --> released in thylakoid space Cytochrome complex transfers 4H+ into thylakoid space 6H+ in total

Chloroplast ATPase

14 c-ring subunits in plants wheres mammal ATPase has only 8 subunits Protein gradient ONLY as membrane is permeable to Mg2+ and Cl-, so Cl- moves to side where more H+ Very low pH 4

Mitochondria ATPase and H pumping

Pump protons across, uses proton gradient and electrical gradient pH= 6.5-7

Difference between mitochondria and chloroplasts

Chloroplasts more reliant on pH (H+ gradient) Chloroplast inner membranes are permeable to Cl- and Mg2+

Why is there a larger difference required in chloroplasts than mitochondria

Only H+ gradient used in chloroplast

What is reduced in mitochondria and chloroplast respectively

Oxygen as electron acceptor NADP as electron acceptor

Difference between how mitochondria and chloroplast add H+ adjacent membrane

Chloroplast PS2 adds H+ to thylakoid space through splitting H2O, mitochondria consumes O2 Mitochondria have actual H+ pumps- complex 1 and 3

Structure of chloroplast

4-5 um Stroma contains enzymes, dna, ribosomes, rna Thylakoid stacks called grana

Why have cyclic electron flow?

Produces ATP only (NO NADPH) Some bacteria only have PS1 Mutant plants without cyclic flow still grow, but not in bright light

Thylakoid lumen

Where the protons are pumped across membrane into lumen

Stroma lamallae

Connect grana

Glycogen

Storage in cytosol Accessed rapidly, water insoluble, efficiently accessed Large polymers don't attract water as much as small glucose molecules and so don't swell

What releases glycogen

Liver (8-10% wet mass) and Kidney Muscle (1-2%)- space in muscles low

Glycogen structure

Degraded and built up from one end a- 1,4 (straight) and 1,6 (branched)

What does branching allow

rapid synthesis and degradation of glycogen and enzymes can work simultaneously at several ends

Hexokinase and glucokinase

Hexokinase, has lower Km (high affinity)

Biochemistry Flashcards

(60 cards)