Carbohydrates Flashcards
why are carbs highly oxizable?
Beacuse of the ‘high energy’ associated hydrogen electrons.
Carbohydrates are a amjor source of?
Energy
What can carbs store?
Potential energy
Name some other functions of carbs.
They have structural and potective functions.
Contribute to commuinication between cells.
What kind of potential energy do plants store?
Starch
What kind of potential energy do animals store?
Glycogen
What structural support do carbs give in plants?
Cell walls.
What structural support do carbs give in animal?
Extra cellular matrices
Name the three types of monosaccharides that are important in humans?
Glucose, galactose and fructose.
Name the three important disaacharides in humans.
Maltose, sucrose and lactose
How are dissacharides formed?
Monomers that have been joined toegther by glycosidic bonds.
Which dissacharide is the main sugar found in milk?
Lactose
Which dissacharide is the sugar we would buy from the shop?
Sucrose
Which disaccharide is the breakdown product of starch?
Maltose
What are polysaccharides?
Polymers of medium to high molecular weight.
Define homopolysaccharide
Single monomeric species
Define heteropolysaccarides.
Have two or more monomer species.
Name the two types of glucose polymer found in starch.
Amylase and amylopectin.
90% of glycogen is found in two places. Name them.
Liver and skeletal muscle.
What does the glycogen in the liver do?
Acts to replenish blood glucose when fasting.
What does the glyogen in the skeletal muscle do?
catabolism produces ATP for contraction.
Describe why glusocse is stored in polymers.
- It’s compact.
- Amylopectine and glycogen have non-reducuing ends meaning they can be readily synthesised and degraded.
What are glycoproteins?
Proteins that have carbs covalently attached.
The % of carb content in glycoproteins varies between?
1-80%
When carb attach to proteins, this may…
- Increase protein solubility
- Influence protein folding and conformation
- Protect it from degradation
- Act as commuinication within cells.
What is GAG short for?
Glycosaminoglycans
well done if you get this hehe
What are GAGs?
Linear polysaccharides consisting of repeating dissaccharide units.
What are proteoglycans?
They attach to GAGs covalently and are macromolecules found on the surface of cells or between cells in the extracellular matrix so they form many connective tissues.
In Glycoproteins, what is in abundance?
Protein.
Where are glycoproteins found?
Usually found on the outer plasma membran and extracellular matrix but can also be found in the blood and cells in the secrtory system.
What are mucopolysaccharidoses?
A group of genetic diseases caused by the absence or malfunction of enzymes.
what problems canmucopolysaccharidoses lead to?
Severe dementia, problems w the heart
What happens in individuals w Hurler’s sydrome?
They have severe development defects.
What are some of the symptoms of Hurler’s syndrome?
Clouding and degredation of the cornia,thickening of the arterial wall.
Where in the diet can you find-
1. Starch
2. Glycogen
3. Cellulose/ hemicellulose
4. Oligosaccharides
5. Lactose, sucrose, maltose
6. Glucose, fructose
- Cereals, potatoes, rice
- Meat
- Plant cell walls (don’t digest these but still help with the process of digestion).
- Peas, beans, lentils
- Milk, sugar, beer……
- Fruit, honey.
Describe the process of digestion in regards to the journey taken.
Mouth- salivary amylase breaks down starch.
Stomach- n digestion takes place here.
-Duodenum- panceatic amylase which also breaks down starch.
Small intestine- final digestion by musosal cells takes place.
What are the three main products of digesion?
Glucose, galatose, fructose.
What happens to these products obtained during digestion?
The gut absorbs them into the bloodstream.
What is the absorbtion of glucose powered by?
ATP
Cellulose and hemicellulose cannot be digested by the body but what d they provide?
They increase faecal bulk.
Some people have disacchardie defiency because of genetics.
Name some other reasons why people ay have them.
Severe intestinal infection.
Other inflammation of the gut lining
Drugs injuring the gut wall.
Surgical removement of part of the intestine.
What are polymers broken down by?
Gut bacteria,
What are the symptoms of disaccharide deficiencies?
Abdominal distension and cramps.
What is the most common disaccharide defiency?
Lactose intolerance.
Why does lacose intolerance occur? (2).
- Undigested lactose is broken down by gut bacteria causing gas build up and irritant acids.
- Lactose is osmotically active, drawing water from the gut into the lumen hence causing diahorrea.
Where does glucose diffuse through?
Intestinal epithelium cells into the portal blood and on to the liver.
What happens to glucose after it has diffused?
It is immediatly phosphorylated into glucose 6 phosphate.
Why can’t G6P diffuse out of the cell?
GLUT transporters do not recognise it, trapping it in the cell.
90% of glycogen is found in both…
Liver and skeletal muscle.
What happens to glycogen in the liver?
Blood glycogen falls.
What happens in the skeletal muscle to glyogen?
There is no G6P
Define glycolysis.
The degradation of glucose in a series of complex reactions that do not require oxyegn.
What is the purpose of glycolysis?
To yield ATP as an energy source.
Describe the amount of ATP obtained by the process.
For each molecule of glucose, 2ATP is required for the process. 4ATP are produced leaving a net gain of 2ATP.
How much ATP does the phosphorylation of glucose require?
1ATP
Why does NAD+ need to be regeneretaed?
Without NAD+, there is no glycolysis.
Where does NAD come from and how does the body get it?
Niacin (essental vitamin) and the body gets it through the diet.
Redox balances require the…
REplenishment of NAD+ as is required for the reducton of various intermediate metabolites.
Draw out the glycolysis cycle.
:)
What is glucanogenesis?
A metabolic pathway that results in the generation of glucose.
Name some tissues that reply completely on glucose for their main source of energy.
Brain, nervous system, red blood cells, testes.
How much sugar does your body need in a day?
How much does your brianeed ?
160g. Brain needs 120g of this.
How many of the glycolysis reactions are reversible?
7
If the delta G is positive what does this mean?
What about negative?
Positive=must add energy to a reaction.
Negative= energy released from a reaction.
How many reactions are there that bypass the three irreversable reactions of glycolysis?
4
Describe reactions A and B
Pyruvate is transported into the mitochondria where it is converted to oxaloacetate. It is then converted to maltate. Maltate gets transported into the cytoplas and then is converted back in oxaloacetate. This is finally turned into PEP.
What does reaction C do?
Converts Fructose 1,6 biphosphate into fructose 6 phosphate.
What does reaction D do?
The dephosphorylation of glucose 6 phosphate into glucose.
