W3 - Macro - Proteins

Question 1

What atoms are protein made up by?

Answer 1

Same as carbs & lipids, Carbon (C), Hydrogen (H) and Oxygen (O) but also Nitrogen (N) (giving the name amino (containing N to amino acids)

Question 2

What does protein mean?

Answer 2

Of prime importance

Question 3

How are proteins used by the body?

Answer 3

Whenever the body
is growing, repairing or replacing
tissue, proteins are involved. Sometimes their role is to
facilitate or to regulate, at other times its to become part
of a structure

Question 4

How are proteins different to amino acids?

Answer 4

They are made up of (about 20 common) amino acids

Question 5

What are unique side groups?

Answer 5

The things that distinguishes each amino acid from each other. all have the same basic structure - a C atom, with a H atom, an amino group and an acid group, however C atoms need to form 4 bonds - the 4th bond is the unique side group. This makes protein v. complex. Glycine is a simple amino acid with a H atom as it’s side group. Alanine, has an extra C with 3 H atoms. Others have more comlex side groups.

Question 6

What is the difference between essential and non essential amino acids?

Answer 6

Essential not made by the body. Conditionally essential if the body not able to make for itself

Question 7

Do proteins in food become body proteins directly?

Answer 7

No they supply the amino acids from which the body makes its own proteins. Food also provides N to build the non-essential amino acids and other N containing compounds the body needs

Question 8

Where does protein digestion begin and how?

Answer 8

In the mouth where they are crushed and moistened

Question 9

How does the stomach contribute to protein breakdown?

Answer 9

Hydrochloric acid uncoils (denatures) each protein’s tangled strands (allowing digestive enzymes to attack peptide bods). Also helps in release of pepsin, which helps cleave proteins (large polypeptides) into smaller ones and amino acids

Question 10

How does the small intestine contribute to protein breakdown?

Answer 10

These are further hyrolysed in the small intestine via proteases, and then again via peptidase

Question 11

How does the body use proteins?

Answer 11

The human body contains about 30,000 different proteins of which approx 3,000 have been studied. Each of which has a specific fn and that is determined during protein sysnthesis

Question 12

How do proteins make each human unique and what provides their instruction (how they should be synthesised)?

Answer 12

Each human is unique because of small differences in the body’s proteins, which are determined by genes providing instructions to the cells how to synthesise proteins. The sequence of amino acids in each protein (determined by the DNA as it makes strands of messenger RNA) determines it’s shape which supports a specific fn. If a mistake occurs in the sequencing , the protein is altered, the results of which can be dramatic, for exaple sickle-cell anaemia, dimishing the ability of heamoglobin to carry O2

Question 13

What does ‘gene expression’ mean and provide an example

Answer 13

Cells can regulate ‘gene expression’ to make the proteins they need. Nearly all cells posess the ability to make all human proteins, but each type generally makes only the protein it needs. eg cells of the pancreas expresss the gene for insulin; in other cells that gene is idle

Question 14

How do some proteins act as enzymes?

Answer 14

By breaking down, building and transforming substances. Like ministers and judges involved in marriages and the disollution of those marriages, enzymes are not altered by the reactions they facilitate

Question 15

Provide an example of where a protein acts as a hormone

Answer 15

Hormones are messenger molecules, some of which are proteins for example insulin, which stimulates the transport proteins of the muscles and adipose tissue to pump glucose into the cells. ADH & oxytocin are also protein hormones

Question 16

How can proteins affect the body’s fluid balance?

Answer 16

If plasma proteins enter interstitial places fatser than they can be cleared they cause oedema, which causes a reduced capacity to deliver nutrients and O to the cells, resulting in them not functioning properly

Question 17

How do proteins help regulate the acids and bases?

Answer 17

Protein acts as a buffer by attracting excess H ions. Proteins having _ve charges on their surface. H +ve

Question 18

Provide an example of a transporter protein

Answer 18

Some proteins move about in the body’s fluids carrying nutrients and other molecules, for example Hb carries O from the lungs to the cells

Question 19

How do proteins help to protect against infectiions?

Answer 19

If the body ids an antigen it makes antibodies (giant proteins molecules) designed specifically to combat them. Without sufficient protein the body cannot make sufficient antibodies

Question 20

What 3 supplementary roles does protein play in the body?

Answer 20

If there is insufficient carb intake the body will break down protein to make amino acid for glucose producttion. They also play a role in blood clotting and vision.

Question 21

What are the two factors that determine a protein’s quality?

Answer 21

High quality proteins deliver the essential amino acids the body needs, low quality do not. The quality is determined by (1) digestibility (animal is higher than plant 90-99 vs 70-90%) & (2) amino acid composition (if there is not enough of any esssential amino acid, protein synthesis is limited, the amino acid in question being termed a limiting amino acid). Gnerally foods from animals provide high quality proteins (‘cep gelatin) whereas plants tend to be limited in one or more essential amino acids. This can be managed by combining different plants into the diet and therefore different but complementary amino acids resulting in complementary proteins

Question 22

What’s reference protein?

Answer 22

The essental amino acids requirements of preaschool age children which other food proteins are compared determining it’s quality

Question 23

What are the consequences of Protein Energy Malnutrition (PEM)?

Answer 23

Poor growth in children and weight loss and wasting in adults

Question 24

What are the two different type of PEM, how are they caused and how do their symptoms differ?

Answer 24

Marasmus and kwashiorkor. The former resulting from severe deprivation of food over a long time resulting in muscles (incl. heart) wasting and impaired brain development. The latter, a sudden and recent deprivation of food, leading to a fatty liver, failure to clear toxins from the body resulting in inflammation and contributing to the swollen bellies. Inability to store iron can also cause illness and death by promoting bacterial growth and free radical damage. The two PEMs can be combined. Amino acids can be diverted away from antibody creation and as a result infections can arise.

Question 25

Name 3 chronic diseases that high protein diets have been linked to?

Answer 25

heart disease, cancer, osteoporosis and kidney stones (but insufficient research to establish upper lvl)

Question 26

Can protein help in weight control and if so how?

Answer 26

A study investigated people who were deliberately overfed. Both groups gained weight, however the low protein group 1/2 as much as the higher protein group. Almost all of their’s being stored as fat whereas the higher protein group stored about 1/2 the excess Kj as fat & gained lean body tissue

Question 27

Why is there a RDI of protein and what is it?

Answer 27

To help people work out how much they should have per day. 0.84g per kg fro M and 0.75 for F

Question 28

What might be an alternative to whey protein and why?

Answer 28

If not enough protein is secured from standard food sources, they can drink milk to supplement

Question 29

Do single amino acid naturally occur in foods and do they offer a benefit to the body?

Answer 29

No and they offer no benefit to the body , in fact can be harmful

Question 30

Does ordinary food contain branched chaim amino acids anyway?

Answer 30

They do (in abundance) and compared to glucose and fatty acids they provide very little of the (advertised) ‘fuel’ for muscles