week 6 - nutrition and digestion Flashcards
1
Q
food
A
raw materials that fuel our bodies - but it needs to be broken down into its molecular form in order to be absorbed
2
Q
digestion
A
the incorporation of nutrients into the body
3
Q
path of digestion
A
- mouth
- esophagus
- stomach
- small intestine
- large intestine
- anus
4
Q
digestion and ingestion at the mouth
A
- teeth break down food into smaller pieces to form bolus (mass of food)
- enzymes in saliva to break down carbs (salivary amylase)
- food goes into the stomach
5
Q
digestion at the stomach
A
- physical breakdown of food through muscle contractions
- acidic environment kills pathogens
- enzymes break down carbs and proteins (not lipids yet)
6
Q
digestion and ingestion at the small intestine
A
- bile released into small intestine
- bile helps digest and absorb lipids (fats)
- digestion of proteins and starches complete
- nutrients are absorbed into the bloodstream
- what is left of the chime will be moved into the large intestine
7
Q
absorption and elimination at the large intestine
A
- depending on the needs of the body, water and salts are absorbed/not absorbed
8
Q
secretion at the anus
A
what is left of the chime and the bile gets secreted (poop)
9
Q
bolus
A
mass of food
10
Q
enzyme
A
type of proteins that allow molecules to attach and catalyze a chemical reaction to break bonds
11
Q
what are enzymes named after?
A
what they are helping (ex. lactase is going to catalyze lactose)
12
Q
catalyze def.
A
to make the reaction happen faster (ex. putting a rocketship on the back of the molecule)
13
Q
how are nutrients absorbed?
A
through membranes
-the more surface area of the membrane that contacts food, the more nutrients that are likely to be absorbed
-small intestine is designed to maximize surface area
14
Q
three major types of macromolecules
A
- carbohydrates
- nucleic acids
- proteins
15
Q
carbohydrates
A
chains of carbons that are bonded to H and OH groups
- made up of C, H, and O
- primary source of fuel for cellular mechanisms are carbs
16
Q
monosaccharides
A
simple sugars have a single molecule
-fast energy and readily available
17
Q
three examples of monosaccharides
A
glucose, fructose, and galactose
18
Q
disaccharides
A
2 molecules (ex. lactose)
19
Q
polysaccharides
A
3+ molecules
-also called complex carbs or starch
-monosaccharides are linked together
20
Q
why cant we digest cellulose?
A
we dont have the enzyme to break down beta linkages, only alpha linkages
-what we cant digest turns into fiber
21
Q
difference between starch and cellulose
A
starch links point down and cellulose links point up and down
22
Q
example of starch
A
potatoes, bread, rice, pasta, cereals, etc.
23
Q
examples of cellulose
A
plants, wood, wool, silk
-can be extruded into a fiber
-we CANNOT digest this
24
Q
fiber
A
types of indigestible plant carbohydrates
-helps provide solid mass for chyme to bond to
-sweeps or stimulates mucus to remove toxins
-bonds with bile to reduce amount of fat entering bloodstream and less fat is absorbed
25
three types of lipids
1. fatty acids
2. phospholipids
3. sterols
26
what do lipids do?
form hormones and cell membranes, also provide insulation
27
two types of fats
unsaturated and saturated
28
saturated fats chemically and non chemically
linear structure where each carbon is attached to 2 hydrogens
-stacked, so they can be dense and difficult to break down
-solid at room temperature
29
unsaturated fats chemically and non chemically
-some of the carbons form double bonds and creates a bend in the structure (less stable)
- harder to stack, so less dense and easier to break down
-liquid at room temperature
-can improve blood cholesterol, stabilize heart rhythm, etc.
30
phospholipids
form cell membranes and control flow of chemicals in and out of cells
-2 hydrophobic tails and a hydrophilic heads which allows water to pass over the head of the cell
31
sterols
regulate growth and development
-cholesterol and steroid hormones
32
cholesterol
can attach to and thicken vessel walls and may cause serious health problem
33
steroid hormones
regulate sexual development and sex cell production and maturation
34
what does estrogen stimulate/influence?
influences memory and mood
35
what does testosterone influence/stimulate?
stimulates muscle growth
36
proteins
polypeptide chains of amino acids that fold into specific 3D shapes
-used for structure, repair growth and catalysis
37
how many amino acids do we need?
20 for our daily chemical process, but we only produce 12 of non essential amino acids
38
complete proteins
animals, soy, tofu...
39
how do we get the other 8 amino acids?
we have to eat them
40
incomplete proteins
most plant proteins only 6 of the 8, why vegetarians need to supplement with extra stuff or fake meat
41
vitamins
organic molecules necessary in small amounts
42
two types of vitamins
1. fat soluble (a, d, e, k)
2. water soluble (b and c)
43
minerals
inorganic elements necessary in small amounts
44
4 important minerals
1. calcium (CA2+)
2. phosphorus (P)
3. potassium (K+)
4. chlorine (CL-)
5. sodium (NA+)
45
calcium (CA2+)
helps bones and muscle contractions
46
phosphorus (P)
important in nucleic acids, phospholipids, atp
47
potassium (K+) and sodium (NA+)
electrochemical gradient in action potentials
48
chlorine (CL-)
helps maintain fluid pressures
49
type of water molecule
polar molecule
-one side is more positive and the other is more negative
-polarity makes it cohesive so it can bond with other molecules
-hydrogens held together with covalent bonds
-linkages in between are hydrogen bonds
50
chyme
mass of food when it enters our stomach
51
why do we need energy?
to do things that dont happen spontaneously
-walking around, staying awake, reproduction
52
where does fuel come from?
comes from energy stored in chemical bonds
-photosynthetic organisms create it initially
53
chemical bonds
where you can store your energy
54
how is photosynthesis like eating in reverse?
put energy in from the sun and build up bonds in carbs, later get converted into other things
-breaking bonds and reforming new bonds releases energy can be harnessed to do "work"
55
hydrocarbons
molecules with chains of carbon and hydrogen atoms (5 - 12 carbons)
-within bonds energy is stored
forms new bonds, relaeses energy that can be harnessed, combusts and create something
-then harness extra energy to do things
56
what do we do if we want to store energy?
store it in the form of lipids because that will give you the most energy in the form of lipids (fat)
57
tristearin
a triglyceride derived from three stearic acid molecules (fatty acids)
-obtained from animal fats and some plant fats
-solid at room temperature
58
why are triglycerides good for energy storage?
long hydrocarbons with many bonds that can be broken, releasing energy; makes them good for energy storage
59
molecule
bunch of bonds that have energy stored in them
60
why do humans have taste preferences? (fats)
humans tend to prefer foods with higher fat concentration
-increased sugar content also increases preference to a certain point
-increased fat content increases preference to no end
61
what happens when countries get richer?
reduce consumption of complex carbs, increase in sugar and fat consumption
62
why have evolved to have a taste preference?
lipids contain higher amounts of energy per gram of any macromolecule (carbs and proteins)
63
how does chemical structure affect digestion and metabolism?
cant digest cellulose in plants, cant eat the cell wall
64
amino acids
"the building blocks of protein"
-amino acids build them together
-rips off simple sugar and binds to carbohydrate
65
what is good about protein?
have to consume protein in order to create new tissue and muscle, and need it for growth
66
why do some people have curly hair and some others don't?
instructions on how to make hair but carry different amino acids to link together, and depending on what they are, they are going to make the fiber for hair curl or link straight
67
how much is one kilocalorie
1000 calories
68
BMR
basal metabolic rate
-energy needed to maintain life without any activity stress growth, etc.
69
how many calories do women and men need a day?
female - 1800 to 2400
male - 2400 to 3200
70
how many calories do humans make with bmr
female - 1400
male - 1700
71
what factors influence an organisms metabolism
1. body size
-total energy usage goes up
-metabolic rate goes up
-metabolic rate per gram goes down
2. body temperature
-endotherms (maintaining temperature thats higher than outside temperature) go up
-ectotherms
3. activity
-with increasing activity metabolism goes up (oxygen consumption)
72
why do animals have taste preferences for fats over carbs and proteins?
because their fitness is higher and they do not have to eat as much food
73
levels of ingestion
1. teeth tear/grind food and increase the surface area
2. salivary mucous and a - amylase breaks down the starches and cleave off simple sugars
3. tongue secretes lipase and breaks down lipids
4. food goes down esophagus and into the stomach
74
what is the small intstine good for?
specialized for absorption of small molecules
-has mucose and submucosa
75
mucosa
secretes enzymes, absorbs nutrients
76
submucosa
blood vessels, lymph vessels and nerves
77
two levels of digestion
1. sphincter closes, prevents regurgitation
2. stomach churns and secretes
78
levels of absorption
1. pancreas secretes fats, carbs, and proteins
2. small intestine microvilli secrete and breaks down enzymes into their simple sugars
3. liver secrets and starts pump out bile
4. absorption occurs throughout
79
bile
detergent that breaks up clusters or fats
80
levels of elimination
1. peristalsis pushes contents into colon
-few nutrients, lots of water
2. fiber increases speed through the colon
3. colon contains huge populations of bacteria
-consume unabsorbed nutrients, produces vitamins
81
where are nutrients absorbed?
in the small intestine
82
where is water absorbed?
in the large intestine
83
what do vitamins and minerals support?
biochemical processes, usually by serving as parts of enzymes involved in metabolic processes
84
what three things can excess consumption of vitamins lead to?
1. excess of vitamin can lead to hair loss in men
2. excess vitamin d can lead to growth retardation
3. liver damage can result from excess vitamins and minerals
85
who might need vitamin supplements? (5 things)
1. pregnant or breastfeeding women
2. people on extreme caloric restriction
3. people with low milk consumption and extremely low sun exposure may need vitamin d
4. people with absorption problems
5. women who lose an unusually large amount of blood during menstruation may need extra iron
