Protein

Question 1

What are the 4 parts of a proteins chemical structure?

Answer 1

-Amino group
-Alpha carbon
-Carboxyl group
-R group

Question 2

What is the function of the R group?

Answer 2

-it gives amino acid its properties

Question 3

Describe the primary structure of proteins?

Answer 3

• sequence of amino acids arranged in polypeptide chain
  -formed by covalent peptide bonds between the amine and carboxyl groups of adjacent amino acids

Question 4

Describe the secondary structure of proteins?

Answer 4

-the repeated folding of polypeptide chain to form alpha helixes and beta pleated sheets
-Due to hydrogen bonding between amine and carboxyl groups of non adjacent amino acids
–Provides stability

Question 5

Describe the tertiary structure of proteins?

Answer 5

• the coiling of the polypeptide chain to form a complex molecular shape (3D structure)
  -Caused by interactions between R groups
  –Is important for the function of the protein

Question 6

Describe the quaternary structure of proteins?

Answer 6

• multiple polypeptides interacting to form a single, larger, biologically active protein
  -Can be held together by a variety of bonds

Question 7

What happens to proteins in the stomach during digestion?

Answer 7

-High acidity in stomach causes proteins to denature making them more vulnerable to digestive enzymes
-Pepsinogen is also secreted in the stomach converting it to pepsin
-Pepsin is a protease which will further breakdown protein and breakdown the connective fibres in meat

Question 8

What happens to proteins in the intestines during digestion?

Answer 8

-Stomach juices enter duodenum and pepsin is inactivated due to the alkali pH of small intestines
-Pancreatic juices contain proteases which digest remaining proteins and polypeptides into tripeptides, dipeptides and single amino acids

Question 9

How are proteins absorbed from the intestines?

Answer 9

-The intestine wall has specific tripeptide, dipeptide and amino acid transporters within it
-This process requires energy as it goes against the concentration gradient
-Tripeptides, dipeptides and amino acids reach the epithelial cells where specific enzymes break them down
-These amino acids then enter the blood via an amino acid transporter

Question 10

what are anabolic reactions?

Answer 10

body builds new proteins for growth and repair

Question 11

what are the catabolic reactions?

Answer 11

breakdown of proteins for oxidation or use in future anabolic reactions

Question 12

what is protein turnover and what is it affected by?

Answer 12

-Is the balance between protein synthesis and protein breakdown
-Is affected by increases and decreases during synthesis and breakdown as it can alter net protein balance

Question 13

what is the effect of resistance training on protein synthesis and breakdown?

Answer 13

-Increases protein synthesis and breakdown equally
-Causes net protein balance to remain the same, meaning the persons muscle would also remain unchanged

Question 14

how can net protein balance be increased after resistance training?

Answer 14

• sufficient protein intake is required
  -This causes protein synthesis to increase and stops elevation of protein breakdown