Chapter 5 book notes Flashcards
1
Q
What does protein mean?
A
“of prime importance.”
2
Q
Proteins help your muscles…
A
-contract, your blood to clot, and your eyes to see.
3
Q
What cannot be built without proteins?
A
-no new living tissue
4
Q
Without proteins, what would have no structure?
A
-bones, skin, and hair.
5
Q
Proteins are chemical compounds that contain what atoms?
A
-hydrogen, oxygen, carbon , AND nitrogen.
6
Q
The nitrogen gives what name to the amino acids that form the links in the chain of proteins?
A
-amino (nitrogen containing).
7
Q
How many different amino acids appear in proteins?
A
-20
8
Q
Amino acid strucure
A
-chemical backbone consisting of a single carbon atom with an amino group and acid group attached to it.
9
Q
The linkage of what structure forms the protein?
A
-backbones
10
Q
Side group of amino acid
A
-varies from one amino acid to another
-makes the amino acid differ in size, shape, and electrical charge.
-makes them distinguishable compared to carbs and lipids.
11
Q
Dipeptide
A
-two amino acids bonded together
12
Q
tripeptide
A
-3 amino acids bonded together
13
Q
Most proteins contain how many amino acids?
A
-few dozen to several hundred amino acids long.
14
Q
What determines a protein shape?
A
-the amino acid sequence of a protein determines the way the chain will fold.
-each amino acid has special characteristics that attract it to, repel it from, the surrounding fluids and other amino acids.
15
Q
What determines the function of a protein?
A
-the different shapes of proteins enable them to perform different tasks in the body.
16
Q
Protein shape & corresponding function:
-globular protein=
-hollow balls=
-stiff, sturdy, rodlike protein=
A
-hemoglobin
-carry and store materials within them
-form tendons (more than 10x long as they are wide)
17
Q
How many highly folded polypeptide chains form globular hemoglobin protein?
A
-4
18
Q
Nonessential amino acids
A
-more than half of amino acids are this.
-body can make these amino acids
-“dispensable”
19
Q
essential amino acids & name them
A
-9 amino acids that are not made within the body and need to be given to by food.
-“indispensable”
-HILLMVPTT
20
Q
EX of a nonessential amino acid becoming essential
A
-body normally makes tyrosine from the essential amino acid phenylalanine.
-if diet fails to supply phenylalanine or make conversion to tyrosine than it becomes a conditionally essential amino acid.
21
Q
Do proteins in foods directly become body proteins?
A
-NO
-food supply’s the amino acids from which the body makes its own proteins.
22
Q
Digestion of proteins in foods:
A
-when a person eats food with protein, enzymes break the long polypeptides into tripeptides and dipeptides and finally the tripeptides and dipeptides are broken down to amino acids.
23
Q
Protein turnover
A
-the continuous breakdown and synthesis of body proteins involving the recycling of amino acids
24
Q
Amino acids must be continuously available to build?
A
-proteins of new tissues
25
new tissues include:
-an embryo
-in muscles of an athlete in training
-a growing child
-in scar tissue that heals wounds
-new hair & nails
26
Less obvious building of new tissues include:
-replacing worn out cells and internal cell structure
EX: intestinal tract cells live for 3-5 days and then shed off so they must be replaced AND cells of skin die and rub off, and new ones grow from underneath
27
What happens when a protein breaksdown? (2 things can happen)
-the amino acids are recycled into other proteins
-the amino acid will be stripped off of its nitrogen and used for energy.
28
About how much of the body's available amino acid is broken down & used for energy?
a quarter.
29
What do researchers use to estimate protein requirements?
-nitrogen balance studies
30
Nitrogen equilibrium
-when nitrogen intake equals nitrogen output
-"zero nitrogen balance"
31
Positive nitrogen status
-the body synthesis more than it degrades
-nitrogen intake exceeds nitrogen output
-protein is being retained in new tissues as they add blood, bone, skin, and muscle to their body.
32
Who is usually nitrogen positive?
-growing infants
-children & adolescents
-pregnant women
-and people recovering from protein deficiency or illness.
33
Nitrogen negative status:
-body degrades more than it synthesizes
-nitrogen output is greater than input
-body loses nitrogen as it breaks down muscle and other body proteins for energy.
34
Who is usually nitrogen negative?
-people who are starving
-or suffering other severe stresses such as burns, injuries, infections, and fever.
35
What distinguishes human beings chemically different from one another?
-minute differences in particular body proteins (enzymes, antibodies, and others).
36
the minute differences are determined by what?
-our proteins amino acid sequences, which are written into the genes inherited from our parents and ancestors.
37
What directs the making of all the body's proteins?
-our genes
38
How many genes does the human body have?
-more than 20,000 genes
39
Where is most of the body's protein found?
-in muscle tissue, which allows the body to move.
-the amino acids of a muscle protein can be released when the need is dire, as in starvation.
40
Functions of proteins (8)
1)structural components
2)enzymes
3)transporters
4)fluid & electrolyte balance
5)acid-base balance
6)antibodies
7)hormones
8)energy & glucose
41
Enzymes
-catalysts essential to all life processes.
-facilitates special chemical reaction, but enzyme remains unchanged (LOOK AT FIGURE 5-4)
42
Proteins as enzymes:.
-proteins facilitate chemical reactions
-enzymes put amino acids together to make needed proteins (proteins make other proteins).
43
Proteins as transporters:
-large group of proteins specialize in transporting other substances such as lipids, vitamins, and minerals around the body.
44
Two examples of proteins being transporters:
1)the protein hemoglobin transports oxygen from the lungs to the cells
2)lipoproteins transport lipids in the watery blood
45
3 major body compartments that contain the body’s fluid:
1)fluid inside blood vessel (intravascular)
2)fluid inside cell (intracellular)
3)fluid in between cells, outside of blood vessels (interstitial or intercellular)
46
How do proteins regulate fluid and electrolyte balance?
-fluids flow back and forth between these compartments, and the proteins in the fluids (as well as minerals) help maintain the needed distribution of these fluids.
47
2 reasons proteins are able to help determine the distribution of fluids in living systems:
1) proteins cannot pass freely across the membranes that separate the body compartments
2)proteins are attracted to water (hold water)
48
Edema
-excess fluid accumulation in the interstitial space
49
Special transport proteins in the membranes of cells continuously..
-transfer substances into and out of cells to maintain balance.
50
What is concentrated inside of cells? outside of cellls?
-inside=potassium
-outside=sodium
51
the balance of the two minerals (sodium & potassium) is critical for?
-nerve transmission & muscle contraction
52
A disturbance in the balance can lead to?
-major medical emergency
-imbalances can cause irregular heartbeats, kidney failure, muscular weakness, and even death.
53
What produces acids and bases?
-normal body processes
54
What carries acids and bases?
-they are carried by the blood to the kidneys and lungs for excretion.
-the blood must do this without upsetting acid-base balance.
55
What is the most tightly controlled conditions in the body?
-blood pH
56
Too much acid in the blood=
-vital proteins undergo denaturation, losing their shape and ability to function.
-acidosis
57
Too much base in the blood=
-similar as too much acid
-alkalosis
58
What protein helps prevent acid-base imbalance?
-albumin
59
How does albumin function?
-it gathers up extra acid (hydrogen) ions when there are too many in the surrounding medium and by releasing them when there are too few.
-ACT AS BUFFERS
60
Protein as antibodies:
-giant protein molecules (antibodies) that are created to combat antigens.
61
antibodies work so swiftly and efficiently that in an healthy individual...
-most diseases never get started
62
Without sufficient protein...
-the body cannot maintain its army of antibodies to resist infectious diseases.
63
Each antibody is designed to destroy a..
-specific antigen
64
immunity
-the bodys ability to defend itself from diseases
-molecular memory
65
Proteins as hormones:
-messenger molecules carried in blood
-glycogen & insulin
66
Proteins as a source of energy & glucose:
-when glucose or fatty acids are limited, cells are forced to use amino acids for energy & glucose.
67
Breaking down of amino acids for energy:
-their nitrogen containing amine groups are stripped off and used elsewhere or is incorporated by the liver into urea & sent to kidneys for excretion in urine
-fragments remained are carbon, hydrogen, and oxygen (like carbs and fat) and can be used to build glucose or fatty acids or can be metabolized like them.
68
Are body proteins stored?
(like how glycogen is stored in liver & muscles OR how fat is as triglycerides in adipose tissue).
-NO
-body protein is only available as working and structural components of tissues.
-so when need arises the body dismantles its tissue proteins and uses them for energy
69
Energy deprivation (starvation) always incurs wasting of ?
-lean body tissue as well as fat loss.
70
too much protein and too little protein can have what kind of affect on the body?
-HARMFUL
71
Protein deficiency:
-when diet supplies too little protein or lacks essential amino acid the body slows its synthesis of proteins while increasing breakdown of body tissue protein to liberate the amino acid it needs to build other proteins.
72
Recognizable consequences of protein deficiency:
-slow growth in children
-impaired brain and kidney functions
-weakened immune defenses
-impaired nutrient absorption from digestive tract.
73
PEM: protein energy malnutrition:
-condition that develops when the diet delivers too little protein, too little energy, or both.
-consequences and causes are complex
74
PEMS has been recognized in people with many chronic diseases such as:
-cancer and AIDS
-& those experiencing severe stresses such as burns or extensive infections
75
Severe acute malnutrition (SAM):
-term used to describe severely malnourished infants and children
-occurs when food is suddenly unavailable, due to drought or war.
76
Chronic malnutrition
-less immediately deadly but still damaging to health
-occurs in areas where food supplies are meager and food quality is low.
77
Each year more than ? million children younger than 5 die, and ?% of these deaths are linked to malnutrition.
-5 million
-45%
-they don't starve but they die from diarrhea and dehydration that accompany infections.
78
Marasmus
- a form of SAM identified by degree of wasting
-lean & fat tissues have wasted away, broken down to provide energy to sustain life.
79
Marasmus characteristics:
-weigh too little for their height.
-upper arm circumference is smaller than normal
-metabolism slows, so child feels cold and ill.
-heart, bones, and muscles deteriorate.
80
kwashiorkor
-less common form of SAM
-edema (fluids shift from out of blood into the tissues causing swelling).
-loss of hair color, patchy scaly skin, sores
81
Marasmic kwashirokor
-dangerous combination condition
-muscles waste, but wasting is not apparent because child's face, limbs, and abdomen are swollen with edema.
82
Chronic malnutrition
-greater # of children live with this
-short for their age (stunting), lack nutrients needed for growth, drink a lot of diluted cereal drinks
-may appear normal but may be no larger at age 4 than at age 2.
83
By what age does a fully nourished brain grows to almost full adult size?
-within the first 2 years of life.
-when malnutrition occurs during these two years it can impair brain development and learning ability, sometimes irreversibly.
84
Excessive protein intake & heart disease:
-protein itself is not known to contribute to heart disease & mortality but some of its food sources may do so.
85
Protein foods sources that contribute to heart disease:
-animal derived protein foods(fatty red meats, processed meats)
-fat containing dairy products
-partially processed meats (lunch meats & hot dogs)
86
What does the excretion of end products of protein metabolism depend on?
-adequate fluid intake
-healthy kidneys
87
High protein intake=
adds to the work of the kidneys, thus in the long run may increase the risk of kidney disease.
88
Dietary protein is necessary for ?
-building muscle tissue but they do not improve athletic performance
89
whey protein
-most popular
-by product of cheese manufacturing
-when consumed after strength training it stimulates protein synthesis and increase lean tissue.
90
Amino acid supplement: Lysine
-promoted to prevent or relieve infections that cause herpes sores on mouth or genital organs.
-does not cure herpes infections
-further studies needed to be done
91
amino acid supplement: tryptophan
-relives pain, depression, and insomnia.
-plays as a precursor for brain neurotransmitter serotonin.
92
Side affect of amino acid supplements
-diarrhea
93
has DRI set a UL for amino acid supplements?
-NO further research needs to be done.
94
People most likely to be harmed by amino acid supplements:
-all women of childbearing age
-pregnant or lactating women
-infants, children, and adolescents
-older adults
-smokers
-ppl with low protein diets
95
RDA daily protein allowance for a healthy adult:
- 0.8 gram per kilogram (2.2lbs) of healthy body weight.
-increases with larger people, infants, children, and pregnant and lactating women.
96
Average protein intake for U.S. adult males is about ?% of total kcalories.
-16%
97
High quality protein
-provide enough of all the essential amino acids needed to support the body's work
98
two factors that influence protein quality:
-proteins digestibility
-amino acid composition
99
Proteins must be ? before they can provide amino acids.
-digestible
100
Protein digestibility depends on:
-proteins source and other foods eaten with it.
101
digestibility of most animal proteins is:
digestibility of plant proteins:
-high (90-99%)
-less digestible (70-90% for most, more than 90% for soy).
102
to make proteins cells must have all the ?
-needed amino acids available at the same time.
103
What organ produces nonessential amino acids that may be in short supply?
-the liver
104
If an essential amino acid is missing, what happens?
-a cell must dismantle its own protein to obtain it, therefore to prevent protein breakdown, dietary protein must supply at least the 9 essential amino acids plus nitrogen containing amino groups
105
can partial proteins be made?
-NO
-the body only makes whole proteins.
106
limiting amino acid
-an essential amino acid that is available in the shortest supply relative to the amount needed to support protein synthesis.
107
Foods with high quality proteins:
-animal foods (meat, seafood, poultry, cheese, eggs, and dairy products).
-GELATIN IS EXCEPTION
108
Protein foods limiting in one or more essential amino acids:
-proteins derived from plant foods (legumes, grains, nuts, seeds, and veggies).
109
Some plant proteins are low in protein quality=
and some are higher in protein quality=
-corn
-soy
110
complementary proteins
-two or more proteins whose amino acids assortments complement each other in such a way that the essential amino acids missing from one are supplied by the other.
111
carbohydrate and fat allow amino acids to be used to build...
-body proteins, instead of being wasted away to provide energy
-KNOWN AS PROTEIN SPARING EFFECT.
112
IS % daily value mandatory for all protein labels?
-NO, but it is required when a protein food makes a claim or is intended for consumption by children younger than age 4.
113
% of daily value of protein, reflects...
-both quantity & quality.
