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Flashcards in Proteins Deck (48)
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1

Protein turnover

Proteins are continually being made and broken down = degradation & synthesis of protein

2

Unlike glucose and fatty acids, amino acids are __ for later use

not stored

3

Out of the protein from the diet, how much is absorbed?

95 % absorbed into free amino acid pool (is then broken down or recycled back)
95% goes to urine

4

How much proteins is being synthesised each day?
What does this mean?

300 g
It means amino acids are being recycled

5

Output of free amino acid pool

aa are broken down (into nitrogen and carbon skeleton)
or recycled into aa pool

6

Zero nitrogen balance

intake = output
in healthy individuals (+body builder)

7

Positive balance

intake > output
body synthesises more than it degrades
ex: growing children pregnancy, recovery

8

Negative balance

intake < output
body degrades more that it synthesises
loss of protein (nitrogen)
ex: starvation, severe stress : burn, infection, injury

9

Nitrogen balance =

N intake - Fecal N - Urinary N

10

Protein is __% nitrogen

16

11

__ g proteins = 1g nitrogen

6.25g

12

Does eating more protein, above the RDA drive protein synthesis?

No
Exercise drives protein synthesis

13

AA can't be fattening, T/F

FALSE
depending on the R group, it goes to glucose or fat

14

First step of breaking down protein

- deamination (removal of the amino group)
produces : ammonia + keto acid

15

Keto acids

= carbon structure without its amino group

16

What can keto acids do?

Enter metabolic pathways
are used for energy or production of glucose, cholesterol fat, ketones

17

If the amino acid is glycogenic what does the carbon fragment produce

glucose

18

If the amino acid is ketogenic what does the carbon fragment produce

ketone bodies, fat, sterols

ex: leucine is ketogenic

19

if a particle nonessential amino acid is not available, cells can make it from __

keto acids

20

The deamination of aa produces __ + __

ammonia + keto acids

21

Given a source of __, the body can make nonessential aa from __

ammonia
keto acids

22

What are 2 ways the body can make nonessential aa

- from keto acids, if given ammonia
- by transferring an amino group from 1 amino acid to its corresponding keto acid (=transamination)

23

Ammonia is converted to __ by the liver

urea

24

Which organ filters urea out of the blood for excretion in urine

kidney

25

Liver disease

high ammonia in blood

26

Kidney disease

high urea in blood

27

Urea provides energy

1.25kcal/g

28

If don't consume enough energy, what will?

carbon skeleton

29

Do RDAs assume adequate energy intake?

yes

30

RDA for proteins (adults)

0.8g/kg/day