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bio 12 > test 4- enzymes and digestive system > Flashcards

test 4- enzymes and digestive system Flashcards

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Biology 101 flashcards
1
Q

What is metabolism

A

The sum of all the chemical reactions that occur in a cell

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2
Q

Whatre anabolic and catabolic reactions, which require and release energy

A

Anabolic: forming large molecules from smaller ones, requiring energy
Catabolic: breaking down large molecules into smaller ones, releasing energy

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3
Q

What does high and low metabolism mean

A

High: means chemical reactions occur more rapidly, so energy production is more efficient
Low: means chemical reactions occur slower, so energy production is less efficient

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4
Q

What is metabolism controlled by

A

Peptide hormones called thyroxin (T4) and triiodothyronine (T3) produced in thyroid gland

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5
Q

What does T3 and T4 do

A

Targets all body cells, increases metabolic rate, and regulates growth and development

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6
Q

Whats an enzyme, can it be used again

A

A protein molecule that functions as an organic catalyst to speed up a chemical reaction without beind consumed
Can be recycled (used again) if not denatured

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7
Q

What are cellular reactions apart of

A

A metabolic pathway, a series of linked reactions

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8
Q

Whatre apoezymes and holoenzymes

A

Apoenzyme: a type of enzyme thats inactive until becoming into the active form (holoenzyme) when activated
Holoenzymes are the complete, active enzyme: apoenzyme + activator

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9
Q

Are already active enzymes holoenzymes

A

No, holoenzymes require an activator

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10
Q

What are the types of activators, which is organic which is inorganic, where do they bind to and where are they from/examples

A

Coenzymes (organic) type of vitamins, binds to active site
Ex. C, k, folic acid (B9)
Cofactors (inorganic) type of minerals, binds allosterically
Ex. Zinc, iron, calcium
Apoenzymes can also be activated with the environment, but theyre (probably) not considered activators

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11
Q

Whatre factors that can increase or decrease enzyme activity

A

Concentration of substrate or enzyme decreasing/increasing
Changes in temperature or ph
Enzyme inhibition

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12
Q

How does an enzymes activity differ when temp is drastically increased, slightly increased, or lowered

A

Lowered: slow down/ frozen at 0 degrees
Drastically increased (around 39 degrees or higher): slow down/denature
Slightly increased: increased enzyme activity

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13
Q

Whatre the types of inhibitors and how do they block binding

A

Noncompetitive: changes shape of enzyme and active site by binding allosterically, so substrate cannot bind anymore
Competitive: interferes with active site by binding to it first, blocking the substrate

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14
Q

Give an example of a permanent inhibitor and an instance of inhibitors acting naturally in the body

A

Ex: pesticides permanently block active sites
Ex: inhibitors prevent enzymes from breaking down neurotransmitters that still need to be used

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15
Q

What is feedback inhibition, give an example

A

Ex. Atp production/ isoleucine binding allostericallly to prevent more threonine from making it
When theres enough of the end product in a metabolic pathway, it can bind non-competitively to an allosteric site on the intial enzyme, E1, acting as an inhibitor

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16
Q

Whats the induced fit model of the enzyme substrate complex

A

When the active site of the enzyme slightly changes in shape to accomodate for substrates (a “hug”)

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17
Q

What is homeostasis and what is a homeostatic mechanism (just the definitions)

A

Homeostasis is the maintence of a regularly constant internal environment (although internal conditions still fluctuate slightly in dynamic equilibrium)
A homeostatic mechanism is how your body maintains homeostasis

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18
Q

What does a homeostatic mechanism include, what do these parts do/ whats the steps

A

A sensor/receptor that senses stimulus, which sends to a regulatory center, which has the output sent to an effector

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19
Q

What is negative and positive feedback, give an example of both

A

Negative: keeps a variable close to its set point
Ex. Too cold: body shivers, blood vessels constrict, sweat glands remain inactive
Positive: brings an “ever greater change” in the same direction (away from homeostasis) as the stimulus, intensifying overtime until the stimulus is gone
Ex. Childbirth (more oxytocin released), blood clotting, certain fevers, digestion of proteins in stomach

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20
Q

What does the endocrine system consist of, why is it important in maintaining homeostasis

A

Consists of glands and tissues that secrete hormones
Hormones released goes into blood to find the target organ, influencing systems

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21
Q

Whatre antagonistic hormones, when are they both used, whats an example

A

A pair of hormones with opposite effects to counteract eachother, used when the stimulus is fluctuating
Ex. Glucagon vs insulin

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22
Q

What are the roles of the digestive system

A

Ingesting food, digesting it/breaking it down into its monomers/nutrients, absorbing the nutrients, then eliminating the indigestible remains

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23
Q

Howre the words elimination and excretion different

A

Elimination: disposal of undigested substances not from the cells (Ex. Fiber)
Excretion: disposal of substances from the cells (typically metabolic wastes (ex. Sweat, bile))

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24
Q

Which biological molecule can be absorbed into the bloodstream without being fully broken down

A

Nucleotides can be absorbed into the bloodstream, but can also be broken down further into the sugar, phosphates, and bases

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25
Q

What is the roof of the mouth formed by, what prevents food from entering the wind passage and nasal cavity

A

Roof of mouth formed by the hard and soft palates that separate the mouth form the nasal cavities (soft palate specifically closes nasal cavity when swallowing)
Epiglottis closes (meets with trachea/wind passage) to prevent food from entering the airway

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26
Q

How does the tongue mechanically digest food, how do the salivary glands chemically digest food (whats the enzyme in the mouth, what does it break down)

A

Tongue moves food in your mouth so youre biting different areas and mixes food with saliva
Salivary glands send saliva with salivary amylase for the digestion of starch/glycogen to maltose in mouth)

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27
Q

What is the consumed mass called after chewing, where does it go (what does the next structure do)

A

Chewed food with saliva is a bolus
Bolus reaches the pharynx, which directs food to the stomach and air to the lungs (contains epiglottis)

28
Q

Where does the bolus go after the pharynx/ what does the next structure do, how does it move down

A

Enters the esophagus, which is a muscular tube that directs it to the stomach
Peristalsis (wave of muscle action) begins in the esophagus and moves food throughout the digestive system

29
Q

What does the cardiac sphincter/valve do

A

Prevents stomach contents from backing up into the esophagus (is typically closed)

30
Q

What does the esophagus lead to, what is particular about the next organ’s structure (think expanding)

A

Leads to the stomach
Has folds in the stomach wall called rugae, helping it expand and hold up to 2 liters

31
Q

What type of digestion does the stomach do, how

A

Mechanical: stomach churns food for 2-6 hrs, mixing the bolus with stomach acid which breaks it into smaller pieces (increasing surface area)
Chemical: gastric juices/ stomach acid contains hcl and pepsinogen, becoming pepsin in hcl and breaking proteins in bolus down into peptides

32
Q

What is the mass of food called after leaving the stomach, where does it go next

A

Goes into the small intestine
Acid chyme

33
Q

Whats special about alcohol relating to digesting

A

Is the only substance that can be directly absorbed through the stomach and into the blood (not the small intestine)

34
Q

Whatre ulcers, where are they commonly found

A

Open sores on lining of body, typically found on the stomach (peptic ulcers)

35
Q

is digestion intracellular or extracellular, what does that mean

A

Extracellular
Enzymes help in cavities, not in the cells

36
Q

What are the three parts of the small intestine (in order of food going through)

A

Duodenum, jejenum, ilium

37
Q

What does the duodenum do, where is it found in the small intestine, what does it contain

A

First 25 cm of small intestine is duodenum
Chemically and mechanically digests food
Contains bile and pancreatic juice

38
Q

What does bile help with, where is it produced and stored

A

Produced in liver, stored in gallbladder
Helps with mechanically digesting lipids (emulsifier, helps them mix with water)

39
Q

What does pancreatic juice contain to neutralize acid chyme

A

Sodium bicarbonate (NA HCO3)

40
Q

What are the enzymes in pancreatic juice, what do they break down

A

Contains:
1. Pancreatic amylase (starch/glycogen to maltose)
2.Nuclease (nucleic acids to nucleotides)
3.Trypsinogen (trypsin when active, proteins to peptides)
4. Lipase (lipids to fatty acids/glycerol

41
Q

What are the enzymes produced in the duodenum wall, what do they break down

A
  1. Peptidase (peptides to amino acids)
  2. Maltase (maltose to glucose)
  3. Nucleosidase (nucleotides to sugar, phosphate, bases)
42
Q

Which parts of the small intestine absorb nutrients, what structure on them helps with it

A

Jejenum and illium absorb nutrients into with their villi

43
Q

Where are nutrients absorbed into (think not just systems but the villi too), which nutrients are absorbed where

A

Cardiovascular system via capillary network
Lymphatic system via lacteal (small lymphatic capillary)
Capillaries absorb a.a, glucose, s, p, b into blood
Fatty acids absorbed by lacteal

44
Q

Why are fatty acids absorbed by lacteals and not the capillary networks of villi

A

Because toxins tend to stick to fats, so they need to be cleansed before entering the bloodstream

45
Q

How is the surface area of villi increased

A

Each villi has microvilli, increasing surface area (Good for absorbing)

46
Q

What does the pyloric sphincter do and where is it found

A

Found betwen the stomach and the small intestine (duodenum)
Regulates passage of partially digested food (chyme) from the stomach into the intestine, preventing chyme from moving too quickly into the small intestine

47
Q

What is special about absorbing biological molecules derived from nucleic acids

A

Nucleotides can be absorbed, but they can also be broken down further

48
Q

What does the large intestine consist of, what does it generally (overall) do

A

Consists of the colon, rectum, and anus
Absorbs water from liquid chyme, salts, and some vitamins to prevent dehydration

49
Q

What do the three parts of the large intestine do

A

Colon: absorbs water, salts, and some nutrients from waste, turning it into feces
Rectum: stores feces until the anus allows for defecation
Anus: the hole in which feces leaves from, controls the release of feces

50
Q

How do we get the urge to defecate, what type of feedback is it

A

Positive feedback (urges get stronger and stronger overtime)
Stretch receptors in rectum send messages to spinal cord and brain

51
Q

What type of digestion occurs in the large intestine, how

A

Facultative obligate anaerobes in feces chemically breaks down indigestible material (food other enzymes couldnt, ex. Fiber) and produce some vitamins

52
Q

What are the accessory organs of digestion, what are accessory organs

A

Organs that assist in digestion, but not part of the digestive tube
Pancreas, liver, and gallbladder

53
Q

How do accessory organs send their secretions (think structures), give an example

A

Sends secretions to duodenum via ducts
ex. (pancreatic and common bile duct (from liver and gallbladder) meet before entering the duodenum, allowing bile and pancreatic juice to be released inside

54
Q

What does the pancreas do besides secreting pancreatic juice

A

Secretes insulin and glucagon to regulate blood glucose levels

55
Q

What does the liver do besides producing bile

A

Stores glucose as glycogen (used in regulating blood sugar levels)
Makes plasma proteins (proteins in blood that maintain concentration of substances and water in blood), they help with transport, enzymes, and blood clotting
Removes bilirubin after breaking down old red blood cells
Detoxifies blood

56
Q

What is the hepatic portal system, why is it unique

A

Is a network of veins, where absorbed nutrients from the intestine travel into to reach the liver, which detoxifies the nutrients before sending it to your heart
Connects the small intestine to the liver, different from other blood vessels because it connects the organs together without going through the heart first

57
Q

What is the stimulus, source, target, and effect of insulin

A

Stimulus: high blood glucose
Source: pancreas
Target: liver, muscle, and adipose tissue/cells
Effect: targets absorb glucose, lowering blood glucose level in cells

58
Q

What is the stimulus, source, target, and effect of glucagon

A

Source: pancreas
Stimulus: high blood glucose
Target: liver, adipose tissue (not muscles because they need glucose)
Effect: takes glucose from targets and adds it back into the blood

59
Q

What is the source, stimulus, target, and effect of gastrin

A

Stimulus: proteins in stomach detected
Source: cells from lower stomach
Target: gastric glands in stomach
Effect: produces gastric juice

60
Q

What is the stimulus, source, target, and effect of secretin

A

Stimulus: acid chyme in duodenum
Source: duodenum wall
Target: gallbladder and pancreas
Effect: releases pancreatic juice and bile

61
Q

What is the stimulus, source, target, and effect of cck
Whats the full name of cck

A

Cholecystokinin
Source: duodenum wall
Stimulus: fatty chyme in duodenum
Target: gallbladder and pancreas
Effect: release pancreatic juice and bile

62
Q

Whats the source, stimulus, target, and effect of calcitonin, what type of feedback is it related to, why

A

Source: thyroid gland
Stimulus: high concentration of calcium in blood
Target: bones
Effects: deposits excess calcium from blood into bones
Negative feedback, release of calcitonin inhibited when blood level of calcium returns to normal

63
Q

What is the source, stimulus, target, and effect of pth, what does it stand for, what type of feedback is it related to and why

A

Parathyroid hormone
Stimulus: low concentration of calcium in blood
Source: parathyroid glands
Target: bones, kidney, intestines
Effect: stimulates the release of calcium from the bone and the reabsorption of calcium by the kidneys and intestine
Negative feedback: release of pth inhibited when blood level is back to normal

64
Q

What is the stimulus, source, target, and effect of calcitriol, what is calcitriol

A

Is an active form of vitamin d
Stimulus: pth
Source: kidney (active form is produced by kidney, inactive is produced by skin)
Target: intestines
Effect: promotes absorption of calcium of calcium from intestines

65
Q

What is the stimulus, source, target, and effect of leptin

A

Stimulus: increased lipid storage (indicates no more energy is needed for now)
Source: adipose cells/tissue
Target: hypothalamus
Effect: decreases appetite

66
Q

What is the effect of too much leptin

A

Too much leptin causes a decrease in sensitivity to the hormone

67
Q

Where do these hormones travel to before making it to their target

A

Bloodstream

bio 12 (6 decks)

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