Module 8 Flashcards
What are the three main amino acid groups?
- Nitrogen containing amine group
- Carboxylic acid
- A side chain
How many amino acids are there?
21
What is a complete protein?
Foods with nine essential amino acids
What are sources of complete protein and in-compete protein
- Complete = animal
- Incomplete = plant
The amino acid that is lacking is called..
Limiting amino acid
What are the steps for protein synthesis
- RNA makes a copy of the DNA code for a particular gene
- The RNA message has a code that controls the sequence of amino acid needed to build the specific protein. These amino acids are drawn from the amino acid pool
How do primary structures arise
- Arise from adjacent amino acids bonding to each other
- Occurs through condensation reaction and leads to formation of a peptide bond
What does peptide bonds lead to
- Polypeptide
- Not yet a protein it must fold into secondary, tertiary or perhaps quaternary structure
How do secondary structures arise
- Hydrogen bonds between non-adjacent amino acids
- Formation of alpha helices and beta-pleated sheets
How do tertiary structures arise
- Interactions between amino acids side chains
- Formation of polypeptide chain
- Might result in functional protein
What are quaternary structures
- Several proteins with a tertiary structure to form a final protein
- Called a protein subunit
What happens when a protein denatures
- Loses its folded 3D structure
- Loses its function
What causes denature of protein
- Acid in our stomach, heat, agitation
- Once denatured it cannot be reversed
Describe the protein digestion process
- Mouth: no chemical digestion, only mechanical
- Stomach: HCL denatures proteins; pepsin chemically digests protein
- Pancreas: secretes pancreatic proteases, including chymotrysin and trypsin
- Small intestine: majority of protein digestion; pancreatic proteases chemically digest protein
- Large intestine: minimal protein digestion
What are the functions for protein
- Body structure
- Transport
- Enzymes
- Movement
- Fluid balance
- Protection from disease
- Energy
What is the protein body structure
- Bones, muscles, skin and every body organ contain protein
What is the main structural protein
Collagen
What is the other key structural protein
Elastin, permits elasticity
Function of transport in protein
- Protein tracks in cells allow substances to walk along them, permitting transport around the cell
- Protein channels regulate movement into and out of the cell
What is the blood protein and what does it do
- Hemoglobin
- Transports oxygen around the body
Function of enzymes in protein
- Most enzymes are proteins
- Speed up rate of reactions
Function of movement in protein
- Myosin and actin are found in muscle
- When myosin proteins attach to actin and kink their heads, muscle contraction occurs
- Allow our bodies to produce movement
Function of fluid balance in protein
- Water is attracted to positive and negative charges of amino acids in blood proteins
- This draw water into the blood and out of the extracellular space
- If blood proteins are low, fluid can build up in the extracellular space leading to edema
Protein protection from disease
- Collagen in skin helps restrict what can enter body
- If infectious agents enter, Y-shaped proteins called antibodies stick to these agents, promoting their removal and limiting the harm they can cause
What is the first line of defence and second line
- First line, collagen in skin
- Second line, antibodies
Function of energy in protein
- Proteins provide 4 kcal/gram
- Amino acids for energy is a wasteful process
- Body prefers to use protein for its various other functions
Synthesis of non-protein substances
- Creatine, DNA, RNA, dopamine and serotonin
What is marasmus
- Occurs when energy and protein are deficient
- Promotes anemia, dehydration, heart irregularities, body temperate dysregulation
What is kwashiorkor
- Believed to occur when protein is deficient, but energy is sufficient
- Evidenced by a distended, swollen abdomen and an otherwise slim appearance
How can protein promote caloric deficit
- Promoting fullness
- Contributing to carbohydrate and lipid metabolism
- Requiring more energy to digest and absorb it
Protein and muscle growth
- Protein muscle synthesis increases in the 24 hours following weight training
- 10g of essential amino acids in the first 2 hours following exercise encourages muscle growth
- Milk-based proteins, for instance, increases muscle strength and improves body composition
Protein and bone health
- In bone, collagen forms a matrix that minerals (ex. Calcium) harden
- However, high protein diets can promote calcium excretion
- Overall, high protein diets do not seem to negatively affect bone health
Protein and kidney health
- High protein diets tax the kidneys because they have more waste products to excrete
- For those with reduced kidney function, consuming protein at the recommended intake level (0.8 g/kg), and not beyond it, is recommended
Protein quality factors
- How well a protein is digested
- How the types and quantities of amino acids in that protein source match the body’s requirements.
What is the PDCAAS
- Compares the amino acid content of a food against a standard amino acid profile. The highest score that can be achieved is 1.0
What is the DIAAS
- Measures how well amino acids are digested in the ileum and more closely estimates the amount of amino acids absorbed by the body
What is the PER
- How much weight an animal gains when consuming a specific amount of protein, divided by the amount of food it consumed
What are branched-chain amino acids
- essential amino acids that have a branched side chain
- They account for 35-40% of the dietary essential amino acids found in body protein
- Have been shown to reduce muscle damage associated with weight training
- Can be consumed from whole sources, do not have to come from supplements
Animal source of protein
- Animal proteins have more total protein, a higher PDCAAS and are complete proteins
- Also, they have vitamin B12 and are higher in vitamin D, iron, zinc and omega-3 fatty acids
- However, they are also higher in saturated fat and are absent in fibre, phytochemicals
- Also, processed animal products (ex. Deli meats, bacon) increase CVD risk/mortality
Risk of vegetarian diets
- They are lower in vitamin D, omega-3 fatty acids, calcium, iron and zinc
- Vitamin B12 is only found in animal products (with the exception of nutritional yeast)
- Supplementation is recommended if these are not sufficient in diet
Benefits of vegetarian diets
- Diets are high in fibre and phytochemicals and low in saturated fats
- Vegetarians are more likely to have lower BMIs, total cholesterol and LDL
- They are also at lower risk for heart disease, cancer and CVD mortality
