Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

MEH > Carbohydrates > Flashcards

Carbohydrates Flashcards

(96 cards)

Start Studying
1
Q

What is stage 1 of catabolism?

A

Breaking down molecules for absorption

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

What is stage 2 of catabolism?
What type of reaction?

A

Break down of metabolic intermediates
Oxidative

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

What is stage 3 of catabolism?
What type of reaction?

A

Krebs cycle
Oxidative

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

What is stage 4 of catabolism?

A

Oxidative phosphorylation
Converts reducing power into ATP

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

What is an example of a metabolic intermediate?

A

Acetyl-CoA

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

Where does stage 1 take place?

A

Extracellular - like the GI tract

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

What type of bonds are broken in stage 1?
How much energy is produced?

A

C-N C-O no C-C
No energy produced

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

Where does stage 2 take place?
What is is also known as?

A

Intracellular
Glycolysis

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

What type of bonds are broken in stage 2?
How much energy is produced?

A

C-C
Some energy as ATP

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

Where does stage 3 occur?

A

Mitochondria

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

What reaction can convert energy without O2?

A

Glycolysis

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

What does stage 4 require?

A

O2

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

Where does stage 4 occur?

A

Mitochondria

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

General formula of carbohydrates

A

(CH2O)n

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

What is sucrose composed of?

A

Glucose
Fructose

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

What is lactose composed of?

A

Galactose
Glucose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is maltose composed of?

A

Glucose
Glucose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Which cells can metabolise glucose?

A

All of them

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Give three cells that require just glucose
Why?

A

Red blood cells - no mitochondria

Neutrophils (white blood cells) - mitochondria used to produce free radicals

Lens of eye - no capillaries, so no O2

Kidney medulla cells - little O2, as cortex uses it

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Where are glucose polymers broken down?
By what?

A

Salvia + pancreas - amylase - starch and glycogen to dextrins
Small intestines - disaccharidases attached to membrane of epithelial cells - break down dextrins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Why can’t cellulose be broken down by humans?

A

No complementary enzyme
Cellulose is Beta - which has a different shape from Alpha

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What causes primary lactase deficiency?
Who does it effect?

A

Absence of lactase persistence allele

Adults

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What causes secondary lactase deficiency?
Who does it effect?
Key fact

A

Injury to small intestine - coeliacs, chron’s

Infants and adults

Is reversible

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What causes congenital lactase deficiency?

A

Autosomal recessive defect in lactase gene

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Three stages of monosaccharide absorption
Active transport - into intestinal epithelial cells by Na-dependent glucose transporter, from apical side Passive transport - (high to low) via GLUT2 into blood Facilitated diffusion - into target cells using transport proteins
26
Why are there so many steps in glycolysis? (3)
- useful intermediates made - can be controlled - parts can reverse
27
Is glucose reduced or oxidised in glycolysis?
Oxidised
28
What is produced in glycolysis?
NADH (2 per glucose) ATP from ADP - net increase of 2 Biosynthetic precursors - used in biosynthetic reaction
29
In what type of tissue does glycolysis happen?
All tissue
30
Is glycolysis reversible or not? Exergonic or endergonic?
Irreversible Exergonic
31
What makes a reaction irreversible?
Large negative DELTA G
32
Is CO2 emitted during glycolysis?
No C6 glucose > 2 C3 pyruvate
33
Two key enzymes of glycolysis
Hexokinase (glucokinase in liver) Phosphofructokinase-1
34
What does phosphorylation glucose at the start of glycolysis mean?
- prevents movement back across plasma membrane, as negatively charged - increases reactivity
35
What is the committing step in glycolysis? What does this mean?
fructose 6-phosphate → fructose 1,6- bisphosphate First step to commit glucose to metabolism
36
What does cytosolic mean?
Occurs in all tissue
37
What type of steps are potential sites of regulation?
Irreversible
38
What is an allosteric enzyme?
The activator or inhibitor binds at another site
39
What site do substrates bind to on an enzyme?
Catalytic site
40
What site do regulatory molecules bind to on an enzyme?
Regulatory site
41
What is the enzyme that controls the phosphorylation of fructose-6-P to fructose-1,6-biP?
Phosphofructokinase
42
Where does allosteric regulation take place for Phosphofructokinase?
Muscle
43
Name what inhibits Phosphofructokinase - allosteric
High ATP High citrate
44
Name what stimulates Phosphofructokinase - allosteric
High AMP High F2,6,BP (Fructose 2,6-bisphosphate)
45
Where does hormonal regulation take place for Phosphofructokinase?
Liver
46
Name what stimulates Phosphofructokinase - hormonal
Insulin
47
Name what inhibits Phosphofructokinase - hormonal
Glucagon
48
What molecule is oxidised in glycolysis?
NAD+ to NADH
49
Why wouldn’t NADH be converted back to NAD+?
O2 supply insufficient No mitochondria
50
What enzyme is required to regenerate NAD+ when it doesn’t happen in stage 4?
Lactate dehydrogenase
51
What reaction does lactate dehydrogenase catalyse? Is it reversible?
Reduction of pyruvate to lactate Yes
52
What causes high lactate production?
Shock Congestive heart disease Major exercise
53
What three factors effect plasma concentration?
Production Utilisation Disposal
54
What is the condition when the plasma mM is 2-5? How is the pH effected?
Hyperlactaemia No change
55
What is the condition when the plasma mM is above 5? How is the pH effected?
Lactic acidosis pH lowered
56
Where is fructose metabolised?
Liver
57
What is essential fructosuria? How would you identify this?
No fructokinase There would be fructose in urine
58
What is fructose intolerance? How would you manage it?
Aldolase missing Fructose-1P accumulates in liver - causing liver damage Remove fructose and sucrose from diet
59
What is fructose phosphorilated into?
Fructose-1P
60
What enzyme hydrolyses Fructose-1P?
Aldolase
61
Where is galactose metabolised?
Liver
62
What is the condition is which you are unable to utilise galactose?
Galactosaemia
63
What causes issues like cataracts when you have galactosaemia?
Galactose enters other reaction pathways Using NADPH - depleting the levels Causing structure damage
64
What is the start reactant in a pentose phosphate pathway?
Glucose-6-phosphate
65
What is produced in a pentose phosphate pathway?(3)
NADPH C5-sugar ribose CO2 No ATP
66
What is NADPH used for?(3)
Reducing power for biosynthesis Maintains levels of GSH Detoxification reactions
67
What is C5-sugar ribose used for the synthesis of?(3)
Nucleotides DNA RNAa
68
What is the rate limiting enzyme in a pentose phosphate pathway?
Glucose 6-phosphate dehydrogenase
69
What molecule enters the kreb cycle?
Acetyl CoA
70
What enzyme catalyses the reaction between pyruvate and CoA to acetylcoA? What is a key fact about the reaction - what does it mean?
Pryruvate dehydrogenase (PDH) Irreversible - key regulatory step
71
Where is PDH found? What is the structure?
Mitochondrial matrix Multi-enzyme complex
72
What is PDH regulated and activated by?
A: reactants - CoA, NAD+, ADP, Pyruvate I: acetyl-CoA, NADH, ATP But the ratio - like NAD+:NADH
73
Where does the Krebs cycle take place?
Mitochondria
74
What is acetyl converted to in the Krebs cycle?
2CO21
75
What do the high energy electrons reduce in the Krebs cycle?
NAD+ FAD+
76
What are the products of the Krebs cycle?
NADH and FADH2 (reducing powers) GTP CO2 Precursors for biosynthesis
77
What is the Krebs cycle also known as?
Tricarboxylic acid cycle TCA
78
Where does a large amount go in the catabolism of glucose? What does the efficency depend on?
Lost as heat Tightness of coupling
79
Where does oxidative phosphorylation take place?
Mitochondria
80
What is the cytoplasm of the mitochondria called?
Matrix
81
How many moles of ATP do NADH and FADH2 produce?
2.5 1.5
82
What does a [H+] gradient create?
Proton motive force
83
Where is adipose tissue found? Why?
Newborns - maintain heat Hibernating animals - generate heat
84
Describe how the levels of ATP and ADP would inhibit oxidative phosphorylation
High ATP:Low ADP No substrate for ATP synthase No inward flow of H+ Conc of H+ in intermitochondrial space increases Prevents further H+
85
What are dextrins?
Small carbohydrate subunits
86
Why are enzyme catalysed steps irreversible in glycolysis?
Very negative delta G
87
What is the significance of hexokinase?
Makes glucose more negatively charged Preventing it from passing back through cell membrane
88
What effect does cyanide have on the electron transport chain?
Prevents the flow of e- through the e- transport chain
89
What enzymes catalyses acetylCoA form pyruvate?
Pyruvate dehydrogenase
90
What is the intermediate in glycolysis that produces glycerol phosphate?
dihydroxyacetone phosphate
91
How is NAD+ regenerated in cells containing no mitochondria?
Lactate dehydrogenase Pyruvate to lactate
92
What would cause a decrease in glycolysis?
Low conc of NAD+ Due to product inhibitomn
93
What 2 key transporters are required for the absorption of monosaccharides into the blood? From where to where? What type of transport is it?
SGLT1 - intestinal lumen to intestinal epithelial cell - active GLUT2 - intestinal epithelial cell to capillary - passive
94
What type of transport is it for glucose from the blood into cells?
Facilitated diffusion
95
Where are GLUT2 transporters found?
Pancreatic beta cells
96
Where are GLUT4 transporters found?
Adipose tissue

MEH (10 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions