Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Y1 Nutrition & metabolism > Carbohydrate metabolism > Flashcards

Carbohydrate metabolism Flashcards

1
Q

Roles of CHO in the body

A

Storage - liver/muscle

Glycated proteins - Glycosaminoglycans eg -

Hyaluronic acid - for skin
Keratan sulfate - cornea, cartilage, bone
Heparan sulfate - animal tissue
Chondroitin sulfate - blood vessels, heart valves, tendons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Glucose uptake definition

A

Glucose being taken from the blood into tissue

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Glycogen synthesis definition

A

Making glycogen from glucose (in muscle/liver)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Glycogen breakdown definition

A

Liver/muscle allows glucose to be used (liver glycogen is moveable muscle isn’t)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Glycolysis definition

A

breaking down of glucose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Gluconeogenesis definition

A

making glucose from carbon sources (liver)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Fructose metabolism key points

A

Happens in the liver - used to make liver glycogen, glucose, lactate & TG synthesis (bad if not active leads to lipid accumulation & insulin resistance)

Taken up in other cells by GLUT 5

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

How is CHO removed from blood (hormonal)

A

Pancreas secretes insulin into blood during eating and as glucose enters blood

Insulin increases glucose uptake & promote glycogen storage

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Glucose in blood removal

A

Taken up by liver cells (facilitated transport down conc grad) through GLUT 2

Insulin receptor detects insulin in blood - increases Glucokinase so glycogen is produced (glucose conc grad maintained)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Glucose returning to blood

A

Enzyme is present to remove phosphate group and release glucose back into blood stream (Glucose -6- phosphatase)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Importance of glucose to the brain

A

Glucose provides energy for turnover and neurotransmitter synthesis

brain 2% body weight uses 20% of total glucose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

How does glucose get into the brain

A

Glucose cross blood brain barrier through GLUT 1 then into a neuron through GLUT 3 or Astrocyte (support cell) via GLUT 1 then into the TCA cycle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What happens if there is too much pyruvate in the brain cells

A

it is converted into lactate in the neuron and transported through the extracellular fluid to the astrocyte which prevents new glucose being oxidised instead it is turned into glycogen and stored

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Positron emission tomography shows? (where is gluicose)

A

Glucose mainly present in brain, heart, bladder

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

How does glucose get into skeletal muscle

A

Facilitated transport via GLUT 4

Insulin receptor stimulate hexokinase creating glucose 6 P (conc grad maintained)

Glucose cant leave once phosphate is attached - stored or oxidised

Liver is better at storage but much more is held in muscle due to mass

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is the role of insulin in the skeletal muscle

A

Can increase amount of GLUT 4 on the membrane (via intracellular signalling - reaction to insulin detection) = more glucose in

17
Q

How does exercise increase the glucose in muscle cells

A

Contractions release calcium which translocate GLUT 4 to the membrane increasing glucose uptake

Process is independent of insulin

18
Q

Glycogen synthesis

A

Glucose -> glucose 6 phosphate -> glucose 1 phosphate -> UPD glucose -> glycogen

19
Q

How is glycogen constructed

A

UPD glucose attaches to glycogenin core

8-10 units attached = pro glycogen

Glycogen synthase (insulin regulated) takes over = macro glycogen

Branching enzyme = branched structure (1-6 bonds (1-4 straight))

20
Q

Glycogen synthase regulation

A

GS normal is inactive (P group attached blocking catalytic site)

Insulin activates protein phosphates removing the p group making GS active - glycogen is made

Adreneline/calcium (from exercise) stimulate protein kinase A = more inactive GS (adding P group)

21
Q

Glycogen breakdown enzyme & regulation

A

Glycogen phosphorylase a (active w/ P group)

Glycogen phosphorylase b (inactive no P group)

regulated by glycogen phosphorylase kinase (GPK) it adds to the P group & Glycogen phosphorylase phosphatase (GPP)

22
Q

Glycogen breakdown stimulatuion

A

Glucagon (from pancreas), Calcium & adrenaline (exercise) stimulates GPK to make active glycogen phosphorylase a

Insulin (during rest) stimulates GPP to remove the P group making glycogen phosphorylase b inactive

23
Q

When is glycogen breakdown inhibited

A

When there is lots of ATP or G-6-P they both inhibit glycogen phosphorylase a

High AMP levels inhibit GPP

24
Q

Key CHO processes during exercise

A

lots of glycolysis (stimulated by calcium/adrenaline)

Reduced insulin (less storage)
Glycogenolysis
Glucose uptake

25
Q

Glycolysis key points & net result

A

Generates ATP & co-enzymes (independent of oxygen)
Makes precursors for fat and protein synthesis

Net results = 2 ATP & 2 NADH

26
Q

Glycolytic enzymes

A 
Hexokinase
Glycogen phosphorylase
Phosphofructokinase
Pyruvate kinase
Lactate dehydrogenase
Pyruvate dehydrogenase
27
Q

Pyruvate dehydrogenase (PDH) control

pyruvate to acetyl coA

A

PDH inactive (w/ p group)

PDH phosphatase removes p group (stimulated by calcium & magnesium from exercise) (inhibited by pyruvate, NAD, ADP, calcium)

PDH kinase adds p group (stimulated by NADH, ATP acetyl coA)

PDH active (wo/ p group)

28
Q

TCA cycle functions

A

decarboxylation of acetyl coA

ATP production

FADH2 production

NADH production

29
Q

Electron transport chain features/role

A

4 large complexes

Electrons pass from electron donors to acceptors

Each acceptor wants the electron more than the last one

Final stage = water

30
Q

Gluconeogenesis key points

A

Liver = glucostat (maintains blood glucose)

First reserve for glucose post absorption

During fasting (eg liver store depleted over night) - more fatty acid & glycerol in blood (cant be used as precursors)

PHD & pyruvate kinase reactions are irreversible

Acetyl-CoA from fatty acids cannot form glucose

31
Q

Gluconeogenesis pathway

A
  • FA -> acetyl coA
  • inhibits PDH
  • Pyruvate diverted to OAA
  • OAA converted to malate (to get across membrane)
  • Use malate-aspatate shuttle
  • Converted back to OAA
  • OAA to PEP
  • PEP reversed to glucose
32
Q

What else does gluconeogenesis do (in fasting conditions)

A
  • TG break down
  • Beta oxidation helps inhibit PDH
  • Glycerol converted to glycerol 3 phosphates & enters reversal process
  • Muscle breakdown (alanine can make pyruvate)
  • Lactate production (muscle & RBC - converted to pyruvate then reversed)

Y1 Nutrition & metabolism (11 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions