lecture exam 2
How does bile work?
1) Detergent properties break up and form micelles with triglycerides and phospholipids in food. 2) Enables lipid degrading enzymes to act 3) Promotes absorption of fats and fat soluble vitamins has an affinity for water and fat so it can bring fat into the water. after emulsification , more fat is exposed to enzymes making fat digestion more efficient.
Digestion of fats in small intestine
Cholecystokinin(cck) signals the gallbladder to release bile(via the common bile duct). Fat is emulsified by bile. Pancreatic lipase flows in from the pancreas via the pancreatic duct. Emulsified fat (triglycerides) become monoglycerides because of pancreatic and intestinal lipase.
building blocks of proteins
What are amino acids?
The nucleus and the cytoplasm of the cell. The DNA stays inside the nucleus but the MRNA leaves the nucleus. The MRNA attaches to ribosomes in the cytoplasm.
What areas of the cell are involved in protein synthesis?
Stomach acid inactivates amylase.
What happens to amylase in the stomach
glucagon liver glucose
What happens to us during low blood glucose? Low blood sugar signals pancreas to secrete ____ into the blood. Glucagon Stimulates: -breakdown of glycogen from the _____. -release of _____ into the blood. end results raised blood glucose glucagon secretion inhibited
pancreas blood glycogen fat
What happens when we have high blood sugar? high blood sugar signals the ______ to secrete insulin into the blood. Insulin Stimulates: -Uptake of glucose from the _____ into the cells -Storage of _____ in the liver and muscles -Conversion of excess glucose into ___ for storage END results lower blood sugar insulin secretion inhibited
electron transport chain
Final energy pathway Happens in inner membrane of mitochondria starts with NADH, and FADH2 creates 28 ATP
gastric lipase
Name?______ Category: Enzyme Produced in: Gastric glands of the stomach Site of release: stomach Action: breaks down some fats into smaller units Note: little fat digestion in the stomach
lingual lipase
Name?______ Category: Enzyme Produced in: Salivary gland Site of release: mouth Action: Digests short and medium chain fatty acids in milk Note: Active in infants, minor role in adults inactivated by stomach acid
pancreatic lipase
Name?______ Category: Enzyme Produced in: pancreas Site of release: small intestine Action: breaks down triglycerides into monoglycerides
Cholecytokinin (CCK)
Name?______ Category: Hormone Produced in: cells of intestinal wall Site of release: cells of intestinal wall Action: signals gallbladder to release bile
Bile
Name?______ Category: complex fluid Produced in: liver Site of release: small intestine Action: emulsification
lactose intolerance
What is this describing? Enzyme lactase is needed to digest lactose, the sugar found in milk.-Highest immediately after birth-Declines with age• If lactose not digested in small intestine, it passes to large intestine. •Undigested lactose in small intestine can cause cramping, abdominal distention and diarrhea.
Soluble fiber
What kind of fiber? Dissolves in water Easily digested by bacteria in colon Found in citrus fruits, berries, beans, and oats Reduces risk for CVD and type 2 diabetes by lowering blood cholesterol and glucose levels May bind to cholesterol, dietary fat, bile acids and carbohydrate decreasing their absorption beans oats barley figs prunes sweet potatoes
insoluble fiber
What kind of fiber? Generally do not dissolve in water Promote regular bowel movements Found in wheat bran, the husk of grains, and many vegetables Not easily fermented by bacteria in the colon. strawberries avocados starwberries whole wheat lentils cereals
peptide bond formed by condensation reaction when an OH group from the acid end of one amino acid and an H atom from the amino group of another join to form a molecule of water.
What type of bonds do proteins have? How are they formed?
in the mouth
Where does digestion of carbohydrates begin?
most carbs are digested in the small intestine and the remnants are digested by bacteria in the large intestine.
Where is digestion of carbohydrates completed?
digestion of fats in the mouth
hard fats begin to melt sublingual salivary gland secrets lingual lipase, but that doesn't do much for any fats but those from milk
1.Monosaccharides, the end products of carbohydrate digestion, enter capillaries of intestinal villi. 2.Monosaccharides travel to the liver via the portal vein. 3.In the liver, galactose and fructose share metabolic pathways with glucose. 4. Glucose is used by most cells in the body for energy.
how are Monosacharides absorbed?
disaccharide enzymes(Maltase, lactase, and sucrase) in the surface of the small intestine cells hydrolyze the disaccharides into monsaccharides Glucose+glucose)(glucose +galactase)(glucose+fructose).
how are carbs digested in the small intestine?
micelles triglycerides chylomicrons lacteal
how are fats absorbed in small intestine? Fatty acids and monoglycerides are emulsified by bile salts to form _____. Fatty acids enter the epithelial cells and link to form ______. Triglycerides combine with proteins inside the golgi body to form _______. chylomicrons enter the ______and are transported away from the intestine.
in excess a small amount gets stored as glycogen and the rest in fat. when inadequate body draws on its glycogen and fat stores for energy. when starving break down of protein (muscle and lean tissue) to amino acids to synthesize glucose. the liver converts fats to ketone bodies.
how do metabolic reactions shift when energy is in excess or inadequate?
none , most occurs in the small intestine.
how much digestion of carbs occur in the stomach?
TCA cycle
middle energy pathway happens in the inner compartment of mitochondria starts with 2 pyruvate from glycolysis turns into 2 ATP, NADH, FADH2, CO2
intestinal tripeptidases
which intestinal enzyme? ______ cleave tripeptides to dipeptides and amino acids
Chymotrypsin
which intestinal enzyme? ______ cleaves at the carboxyl end of phenylalanine, tryptophan, and tyrosine
Carboxypeptidase
which intestinal enzyme? ______ cleaves off amino acid at carboxyl end of peptide
Enteropeptidase
which intestinal enzyme? ______ converts pancreatic trypsinogen to trypsin
ATP
(adenosine triphosphate) main energy source that cells use for most of their work. adenosin and three phosphates
Glycogen
: an polysaccharide composed of glucose; a storage form of glucose manufactured and stored in the liver and muscles. Glycogen is not a significant food source of carbohydrate and is not counted as a dietary carbohydrate in food
Gallbladder
A muscular sac attached to the liver that secretes bile and stores it until needed for digestion
Bile
A substance produced by the liver that breaks up fat particles.
Glycerol
A three-carbon alcohol to which fatty acids are covalently bonded to make lipids
Amino acid demenation
Before entering the metabolic pathways, amino acids are deaminated (that is, they lose their nitrogen-containing amino group). Deamination produces ammonia (NH3), which provides the nitrogen needed to make nonessential amino acids and other nitrogen-containing compounds. Any remaining ammonia is cleared from the body via urea synthesis in the liver and excretion in the kidneys
Where is bile produced?
Bile is produced in the liver.
Specific carriers four amino acids
How are proteins absorbed from the small intestine? ______, on the membrane of intestinal cells, transport amino acids into the intestinal cells. • Virtually no absorption of peptides longer than _____. However, there is abundant absorption of di- and tripeptides in the small intestine. • Infants initially are able to absorb whole proteins to a certain extent likely to absorb antibody proteins from mother's breast milk to give immune protection
hydrochloric acid
How does protein digestion occur in the stomach? ____ uncoils protein strands and activates stomach enzymes: protein-->pepsin&HCL-->smaller polypeptides
Denaturation
In proteins, a process in which a protein unravels and loses its native conformation, thereby becoming biologically inactive. In DNA, the separation of the two strands of the double helix.
Catabolism
Metabolic pathways that break down molecules, releasing energy.
Anabolism
Metabolic pathways that construct molecules, requiring energy.
Pyruvate
Organic compound with a backbone of three carbon atoms. Two molecules form as end products of glycolysis. can be used to make glucose
Lactase
Produced in: Cells of small intestine Site of release: Brush border of small intestine Action: lactose= glucose + galactose
pancreatic amylase
Produced in: Pancreas Site of release: Duodenum of SI Action: Breaks down Polysaccharides to shorter chains and Maltose
Maltase
Produced in: cells of small intestine Site of release: Brush border of small intestine Action: Maltose- 2 glucose
Sucrase
Produced in: cells of small intestine Site of release: Brush border of small intestine Action: Sucrose = glucose + fructose
digestion of fats in the stomach
The stomachs churning action mixes with water and acid. a gastric lipase accesses and hydrolyzes only a very small amount of fat. fat from food seperates into droplets
amino acids
Some ______ can be converted to pyruvate, others are converted to acetyl CoA, and still others enter the TCA cycle directly as compounds other than acetyl CoA. As you might expect, ______ that are used to make pyruvate can provide glucose, whereas those used to make acetyl CoA can provide additional energy or make body fat but cannot make glucose. ______entering the TCA cycle directly can continue in the cycle and generate energy; alternatively, they can generate glucose. Thus protein, unlike fat, is a fairly good source of glucose when carbohydrate is not available. it isnt perferred though.
template mRNA ribosomes tRNA released seperate
The DNA serves as a _____ to make strands of messenger RNA (mRNA). Each mRNA strand copies exactly the instructions for making some protein the cell need" "The ______ leaves the nucleus through the nuclear membrane. DNA remains inside the nucleus" The mRNA attaches itself to the protein-making machinery of the cell, the _______ Another form of RNA, ________, collects amino acids from the cell fluid. Each tRNA carries its amino acids to the mRNA, which dictates the sequence in which the amino acids will be attached to form the protein strands. Thus the mRNA ensures the amino acids are lined up in the correct sequence" As the amino acids are lined up in the right sequence, and the ribosome moves along the mRNA, an enzyme attaches one amino acid after another to the growing protein strand. The tRNA are freed to return for more amino acids. When all the amino acids have been attached, the completed protein is _________ "Finally, the mRNA and ribosome _________. It takes many words to describe these events, but in the cell,40 to 100 amino acids can be added to a growing protein strand in only a second. Furthermore, several ribosomes can simultaneously work on the same mRNA to make many copies of the protein"
Pyruvate
Three-carbon compound that forms as an end product of glycolysis.
Glycerol and small lipids monoglycerides and long chain fatty acids
_____ and ______ such as short and medium chain fatty acids can move directly into the bloodstream. Large lipids such as ____ and _____ combine with bile, forming micelles that are sufficiently water soluble to penetrate the watery solution that bathes the absorptive cells. There the lipid contents of the micelles diffuse into the cells.
Amylase disaccharides monosacharides
_____ breaks down poly saccharides then maltase sucrase, and lactase break down ________ into ______
Monosaccharides active facilitated Facilitated specific
________ are absorbed into the cells lining the small intestine and enter bloodstream. • Glucose & Galactose - _______ transport - ________ diffusion Carbohydrate-rich meal • Fructose - _______transport - ________ transporter
Acetyl CoA
a 2-carbon compound to which a molecule of CoA is attached Amino acids and glycerol can be converted to pyruvate and therefore can provide glucose for the body. Fatty acids are converted to _______ and therefore cannot make glucose. ______ can readily make fat. Whereas most of the body's cells can use glucose, fat, or both for energy, the body must have glucose to fuel the activities of the central nervous system and red blood cells. Without glucose from food, the body will break down its own lean (protein-containing) tissue to get the amino acids needed to make glucose. To protect this protein tissue, the body needs foods that provide glucose—primarily carbohydrate. Eating only fat provides abundant ______, but forces the body to break down protein tissue to make glucose. Eating only protein requires the body to convert protein to glucose. ______enters the TCA cycle, and energy is harnessed through the electron transport chain.
glycogen triglycerides protein
anabolic reactions. these all require energy glucose+glucose=? glycerol+fatty acids=? amino acids +amino acids=?
glucose+glucose fatty acids+glycerol amino acids
catabolic reactions that release energy glycogen= triglycerides= protein=
protein absorption in small intestine.
describing ? -Specific carriers transport amino acids into intestinal cells -Once in the cell they may be used for energy or to synthesize needed compounds -Amino acids not used by intestinal cells are transported across the cell membrane: Then sent to the liver via hepatic portal vein
type 1 diabetes mellitus
diabetes in which no beta-cell production of insulin occurs and the patient is dependent on insulin for survival
function of bile
emulsify fats
Glycolysis or glucose to pyruvate
first energy pathway The breakdown of glucose by enzymes, makes 2 ATP energy and 2 pyruvic acid. Happens inside cell cytosol. Anaerobic (short intense excercise)
Structural materials Enzymes- Hormones- Fluid balance- maintain the volume and composition of body fluids. Acid-base balance- acting as buffers. Transportation- Antibodies. Energy and glucose Other The protein fibrin creates blood clots; the protein collagen forms scars; the protein opsin participates in vision"
functions of proteins
Translation
process of creating proteins from an mrna template. the sequence of nucleotides on the rna is translated into the amino acid sequence of proteins.
type 2 diabetes
progressive disorder in which body cells become less responsive to insulin
hydrochloric acid pepsin
protein digestion in the stomach: produced in gastric glands released in stomach what enzyme?______ -Denatures protein structure. -Activates pepsinogen to pepsin. what acidic fluid?_____ produced in gastric glands released in stomach -Cleaves proteins to smaller polypeptides and some free amino acids. -inhibits pepsinogen synthesis -secreted as pepsinogen (inactive form) activated by stomach acid to pepsin.
beta oxidation
reaction that converts fatty acids to acetyl CoA to enter the Krebs cycle
amino acids
reviews the ways the body can use the energy-yielding nutri-ents. To obtain energy, the body uses glucose and fatty acids as its primary fuels and ______ to a lesser extent. To make glucose, the body can use all carbohydrates, most amino acids, and the glycerol portion of a triglyceride. Fatty acids cannot make glucose. To make proteins, the body needs amino acids. It can use glucose and glycerol to make some nonessential amino acids when nitrogen is available; it cannot use fatty acids to make proteins. Finally, when energy intake exceeds the body's needs, all three energy-yielding nutrients can make fat.
Proteases peptidases
small intestine protein digestion: What enzyme?___ produced in pancreas released in small intestine Action: complete the digestion of proteins into single amino acids What enzyme?____ produced in pancreas released in small intestine action: complete the digestion of proteins into single amino acids
Transcription
the process by which the information in a strand of DNA is copied into a new molecule of messenger RNA (mRNA)
Oxaloacetate
this is a definition of one word. ________role in replenishing the TCA cycle is critical. When _______is insufficient, the TCA cycle slows down, and the cells face an energy cri-sis. ______ is made primarily from pyruvate, although it can also be made from certain amino acids when pyruvate is unavailable. Importantly, ________cannot be made from fat. That _______ must be available for acetyl CoA to enter the TCA cycle underscores the importance of carbohydrates in the diet. A diet that provides ample carbohydrate ensures an adequate supply of ______—because glucose produces pyruvate during glycolysis. This is an intermediate
salivary amylase
what Enzyme? produced in: salivary glands site of release: mouth action: hydrolyzes starch to shorter polysaccharides and maltose note: Short duration stomach acid incativates it
monosacharides are glucose, fructose, and galactose disaccharides are maltose(glucose+glucose) lactose(glucose+galactase) sucrase(fructose+glucose)
what are the monosaccharides and what are the disaccharides
glycolisis, TCA cycle, and electron transport chain
what are the three energy pathways?
Trypsin
what intestinal enzyme?______ -inhibits trypsinogen synthesis -cleaves peptide bonds next to the amino acids lysine and arginine -converts pancreatic procarboxypeptidases to carboxypeptidases -converts chymotrypsinogen to chymotrypsin.
amino acids when they are converted to pyruvate then used to make glucose (glucogenic) or amino acids are converted to acetyl CoA(keto genic) gluco genic can enter tca cycle directly
what structures in protein molecules are used for energy and how
in the cytoplasm inside the cell where the ribosomes are.
where are proteins assembled?
amino acids, glucose and glycerol
which compounds can be used to make glucose?
Intestinal aminopeptidases
which intestinal enzyme? ______ cleave amino acids from the amino ends of small polypeptides (oligopeptides)
intestinal dipeptidases
which intestinal enzyme? ______ cleave dipeptides to amino acids
elastase and collagenase
which intestinal enzyme? ______ cleave polypeptides into smaller polypeptides and tripeptides
