Biochemistry Flashcards
What are the two cellular pathways involved in metabolism?
Catabolism
Anabolism
Define metabolism
The set of life-sustaining chemical interactions that occur within an organism’s cells
What is a carbohydrate?
Carbohydrates are organic molecules consisting of carbon, hydrogen and oxygen
What is a monosaccharide?
Simplest unit as glucose, cannot be further hydrolysed to simpler compounds
What is a disaccharide?
Two monosaccharides are joined by a glycolic chain
I.e.: sucrose= glucose+ fructose
What is an Oligosaccharide?
3 to 10 monosaccharides joined together
What is a Polysaccharide?
More than 10 monosaccharides joined together
How many ATP molecules do normal cells produce during respiration (aerobic+anaerobic)?
2 ATP from anaerobi
38 ATP from aerobic
How many ATP cell do cancer cells produce during respiration?
2 ATP
What is the effect of cancer on cells during respiration?
Cancer cells are more glycolysis-dependent , therefore they require more sugar
How can we target for cancel cell therapy?
Through “fake glucose”(2 DG)= cannot go through glycolysis
if cancer cells are more glycolytic-dependent, then they require sugar more; this means that a treatment which gives them “fake glucose” (which cannot go through glycolysis) will more adversely affect cancer cells rather than healthy cells
What is the major sugar in our diet?
Glucose
All cells in our body can use glucose as an energy course
True or false?
True
What happens to glucose once at the intestine?
Glucose leavens the intestine via the hepatic portal vein and arrives first at thrived
Hepatocytes take up glucose where it is converted to pyruvate in the cytoplasm
What is Glycolysis?
Conversion of glucose to pyruvate in the cytoplasm
What are the phases of Glycolysis?
The energy investment phase
The energy generation phase
What are the steps in the Energy Investment Phase?
- Conversion of glucose to glucose-6-phosphate
- Conversion of glucose-6-phosphate to fructose-6-phosphate
- Conversion of fructose-6-phosphate to fructose-1,6-bisphosphate
- Conversion fructose-1,6-bisphosphate to glyceraldehyde-3-phosphate and dihydroxyacetone phosphate
- Conversion of dihydroxyacetone phosphate to glyceraldehyde-3-phosphate
What are the steps in the Energy Generation Phase?
- Conversion of glyceraldehyde-3-phosphate to 1,3-bisphosphate
- Conversion of 1,3-bisphosphate to 3-phosphoglycerate
- Conversion of 3-phosphoglycerate to 2-phosphoglycerate
- Conversion of 2-phosphoglycerate to phosphoenolpyruvate
- Conversion of phosphoenolpyruvate to pyruvate
What I X-ray crystallography?
The protein analysis technique that can be performed to generate quaternary structures and see protein structures
Clinically, why do you think it is useful to know protein crystal structures?
Clinically speaking, it is important to know protein structures as it allows you to identify which abnormalities may be responsible for particular pathologies, and allows for the application of research methods such as drug
What are the stages of Cellular respiration?
Stage 1: Generation of Acetyl CoA
Stage 2: Citric Acid Cycle
Stage 3: Oxidative Phosphorylation
What happens during the generation of Acetyl coA
Pyruvate oxidation first involves its movement across the mitochondrial membrane by the pyruvate carrier
A cell can use different fuels other than glucose (via glycolysis) to generate acetyl-CoA. It can also use amino acids and fatty acids
True or false? So what does this mean?
True
So carbohydrates, fat and protein all feed into the citric acid cycle
What happens in lipid metabolism?
- Minimal digestion by lipases in saliva
- Stomach stores and emulsifies fatty food. Gradually transferred to duodenum.
- Small intestine: Lipases break fat into free fatty acids that are absorbed by the gut epithelial cells where they are resynthesized into triglycerols
What are Bile salts?
detergent substances- emulsify fat,
allowing access of enzymes to digest fat.
What are lipoproteins?
Lipids complex with protein to become soluble aggregates
What are the products of lipid digestion?
Glycerol
Free fatty acids
Monoacylglycerols
Diacylglycerols
What are saturated fatty acids?
Simplest form of lipid, usually part of more complex lipid molecules.
All carbons of the tail are saturated with hydrogen atoms (no C=C bonds)
I,e. Stearic acid
What are unsaturated fatty acids?
Not all carbon atoms saturated with hydrogen atoms. Some C=C bonds.
.
I.e.: linoleum acid
What are the major components of dietary fats?
Trialcylglycerol /triglyceride & cholesterol
What are triglycerides ?
Fatty acids stored as an energy reserve (fats and oils) through an ester linkage to glycerol to form triglycerides/triacylglycerols
What happens during lipid digestion?
Lipases in the saliva and in the small intestine break triacylglycerol into glycerol and 3 free fatty acids.
Short chain fatty acids are absorbed directly into the blood stream from the gut epithelial cells and transported to the liver
Longer chain fatty acids and those still attached to glycerol (monoglycerides) are taken up into the ER of the gut epithelial cells and converted back to triacylglycerol for transportation.
What happens to short chain fatty acids after triacylglycerol has been broken down by lipase?
Short chain fatty acids are absorbed directly into the blood stream from the gut epithelial cells and transported to the liver attached to albumin
What happens to longer chain fatty acids after the breakdown of triacylglycerol by lipase?
Longer chain fatty acids and those still attached to glycerol (monoglycerides) are taken up into the ER of the gut epithelial cells and converted back to triacylglycerol for transportation.
What lipoproteins are present in the gut?
Chylomicron VLDL: very low density lipoprotein IDL: intermediate density lipoprotein LDL: low density lipoprotein HDLm high density lipoprotein
What is the role of LDL in lipid transport?
LDL transports cholesterol, phospholipids, triglycerides (bad cholesterol) from liver to peripheral tissues including adrenal glands and gonads
What is the role of HDL in lipid transport?
The role of HDL is to collect fat molecules such as phospholipids, cholesterol, and triglycerides in the cells of the body and transport it to the liver to be broken down
What is another name for HDL and why?
HDL is sometimes known as “good” cholesterol because high concentration of this lipoprotein usually correspond to healthier blood vessels and lower risk of atherosclerosis
What is the composition of HDL?
40-55% protein
3-10 % Triacylglycerol
15-20% cholesterol/CE
What is LDL composed of?
20-25 % protein
7-15% Triacylglycerol
45-50 % cholesterol/ CE
What is another name of LDL and why?
It is sometimes known as “bad” cholesterol because elevated concentrations of LDL are an indicator of an underlying disease such as atherosclerosis and other cardiac diseases.