Chemical Digestion Flashcards
Types of carbs
Monosaccharides
Disaccharides
Polysaccharides
Oligosaccharides
Monosaccharides (carbs)
Glucose, fructose, galactose
Disaccharides (carbs)
Sucrose, lactose, maltose
Polysaccharides (carbs)
Glycogen, starch, cellulose
Oligosaccharides (carbs)
Shorter polysaccharides (6-8 monomers long)
Which carbs are only absorbable?
Only monosaccharides (simple sugar)
Chemical digestion of carbohydrates…
breaks down large carbohydrates into monosaccharides
Salivary Amylase
- Location of production/action?
- substrate
Salivary Gland/Mouth
starch (polysaccharide)
Pancreatic amylase
- Location of production/action?
- substrate
Pancreas/Small Intestine
starch
Dextrinase
- Location of production/action?
- substrate
Brush Border/Small Intestine
Oligosaccharide
Glucoamylase
- Location of production/action?
- substrate
Brush Border/Small Intestine
oligosaccharide
Maltase:
- Location of production/action?
- substrate
brush boarder/small intest
maltose
Sucrase
- Location of production/action?
- substrate
brush boarder/ small intest
sucrose
Lactase
- Location of production/action?
- substrate
brush boarder/ small intestine
lactose
when food reaches the stomach… carb digestion….
When your food reaches the stomach, carbohydrate digestion stops because of the low acidity in the stomach.
Carb digestion… resumes…
Carbohydrate digestion resumes and finishes in the small intestine
Protein (begins and ends?)
Protein digestion begins in the stomach and ends in the small intestine
Dietary protein
We break all these down
Intrinsic protein
Proteins within the body that we can break down to get amino acids
Examples of intrinsic proteins?
Channel proteins of cells
Enzymes
Proteins within mucosal cells
Protein digestion enzymes
pepsin rennin trypsin chymotrypsin carboxypeptidase aminopeptidase dipeptidase
Pepsin; (protein digest enzyme)
location of production?
cheif cells
rennin; (protein digest enzyme)
location of production?
job?
babies
- Breaks down casein in the small intestine
- As we age, we stop making rennin
Trypsin;(protein digest enzyme)
location of production?
job?
Inactive form comes from Pancreas
-Called Trypsinogen
Works on polypeptides in the small intestine
Activated by enterokinase/enteropeptidase in the small intestine
chymoTrypsin;(protein digest enzyme)
location of production?
activated by?
Inactive form comes from Pancreas
-Called Chymotrypsinogen
Activated by trypsin
carboxypeptidase;(protein digest enzyme)
location of production?
activated by?
Inactive form comes from Pancreas/brush border
-Called Procarboxypeptidase
Cleaves single amino acid off the end of polypeptide
Activated by trypsin
aminopeptidase;(protein digest enzyme)
location of production?
activated by?
brush boarder
Cleaves single amino acid off the end of polypeptide
dipeptidase;(protein digest enzyme)
location of production?
splits into?
brush boarder
Splits dipeptide into 2 single amino acids
Lipase (lipid digstion)
- Breaks down lipids into free fatty acids and monoglycerides (glycerol and one fatty acid)
- Produced in the pancreas
- Produced in small amounts by chief cells in the stomach
Pancreatic nuclease (nucleic acid digest)
- Breaks down large nucleic acids in the small intestine
- Produced in the pancreas
nucleosidase (nucleic acid digest)
Products from pancreatic nuclease are the substrates for nucleosidase
Produced in the brush border
Phosphatase (nucleic acid digest)
Produced in the brush border
What are nucleic acids broken down into?
nucleotides (A,G,C,T,U)
Absorptive processes
active transport
simple diffusion
Active transport; absorptive processes
- Moves non fat-soluble molecules into the villi blood capillaries
- Uses endocytosis or channel proteins
- Requires energy
- Nutrients are delivered to liver for storage or conversion
Simple difffusion; absorptive processes
Moves fat-soluble molecules into villi lacteals
- Fat soluble molecules do this
- Mostly lipids
Aided by micelles
Fat-soluble molecules are delivered into circulation by the lymphatic system
Nutrient
Any substance that is used by the body to produce energy, promote cell growth, or used for maintenance and repair of the cell
If we do not immediately need the nutrients we take into the body, we can store them for later
Examples of nutrients
- Glycogen is stored in the liver and muscles to use for energy purposes later
- Lipids are stored in adipocytes as triglycerides for energy use later
Water
60% of the volume of food we eat is water
We don’t use the water to produce energy, nor growth/maintenance
- Water isn’t used as an energy source
- Water is not used as a building block in cells
We use water to make the things we take in become biologically active
Carbohydrates
Obtain small amount of carbs from animal sources
Obtain most carbs from plant material, fruits, and vegetables.
Lipids
Obtain from both plants and animals; mostly animals
Obtain mostly neutral fats
-Triglycerides, and triglycerols
Animal fat is saturated and solid at room temperature
Plant fat is unsaturated and liquid at room temperature
Proteins
Obtained from both plants and animals
-Mostly obtained from animals in the human diet
Animal proteins are complete (contain the 9 essential amino acids)
-Not every animal protein is a complete protein
Plant proteins do not have all essential amino acids
- Non-complete protein
- Mixing different sources of plant proteins can provide all necessary amino acids
Vitamins
A balanced diet has all the vitamins we need
-Do not need a vitamin supplement when eating properly
Not used to create energy
Vitamins allow us to utilize other nutrients
Vitamins function as coenzymes
Water soluble vitamins
Water soluble vitamins cannot pass through a cell’s plasma membrane to be stored
-Excess water soluble vitamins are excreted in urine
FAT SOLUBLE VITAMINS
Fat soluble vitamins can pass the plasma membrane and be stored
-Become toxic when stored levels become too high
miNERALS
Function in growth and repair/maintenance of the cell
-NOT energy production
Some foods have minerals in them; some foods have minerals on their surface
eXAMPLES OF MINERALS
- Sulfur helps to make cartilage
- Calcium is deposited in bones to make them stronger
- Calcium is used in muscle contraction
- Phosphorus is important as welL
Metabolism
Sum of all biochemical processes/reactions that our body undergoes
Our body can convert one type of nutrient to another to match the needs of the body with the intake of food we consume
We can’t make essential nutrients; we have to ingest them
-We can convert from one form of nutrient to another
Two categories of metabolism
ana- build up of reaction
cata- break down of reactions
Anabolism
Reactions where large molecules are made from smaller subunits
Catabolism
Large molecules are broken down into their smaller subunits
-Chemical digestion is a catabolic process
Occurs when there is a need for energy
Example:Breaking down glycogen -> glucose
Overview of metabolism
Anabolic reactions form lipids, proteins, and glycogen
Catabolic reactions break large molecules down to pyruvic acid or acetyl-CoA
Cellular respiration occurs in the mitochondria
Anabolic reactions form lipids, proteins, and glycogen (overview of meatbolsim)
Amino acids -> functional/structural proteins
-Ex: Enzymes are functional proteins
Monosaccharides -> glycogen to be stored in tissues
Most anabolic reactions are used to make storage products
Cellular respiration occurs in the mitochondria (overview of metabolism)
Substrate-level reactions occur in the cytoplasm
Products from substrate-level reactions are broken down in the Kreb’s cycle for ATP
Oxidation
Take away a hydrogen or add an oxygen
-Product has a lower energy than reactants
Reduction
Add a hydrogen or take away and oxygen
-Product has a higher energy than the reactants
When one molecule is oxidized, another molecule is reduced
Redox reactions are coupled
Enzymes in redox reactions
dehydrogenases
oxidases
Dehydrogenases (enzymes in redox reaction)
Enzyme that catalyzes oxidation reactions
Pulls off a hydrogen
oxidases (enzymes in redox reaction)
Catalyzes oxidation reactions
Catalyzes the transfer of oxygen
Adds an oxygen
Coenzymes (in redox reaction)
NAD; The reduced form is NADH
FADH;The reduced form is FADH2
Both coenzymes in redox reaction function in what?
as transport molecules
NAD and FADH do what?
bind to hydrogen and carry it from one place to another
-Act as hydrogen acceptors
Substrate-level Phosphorylation
Occurs in the cytoplasm of the cell
Phosphorylation is attaching a phosphate to ADP to make ATP
-Adenosine can bind to a maximum of 3 phosphates
Oxidative Phosphorylation
Occurs if oxygen is present after substrate-level phosphorylation
Uses a chemo-osmotic process (gradient)
-The proton gradient is used to catalyze the conversion of ADP to ATP
The concentration of protons lives in the form of the hydrogen ion (H+)
Carbohydrate metabolism
Glucose enters the cell by facilitated diffusion
Glucose is immediately phosphorylated to glucose-6-phosphate (G6P)
Glycolysis (catabolic breakdown of glucose) continues and results in the formation of:
If oxygen is present, oxidative phosphorylation occurs
If oxygen is not present, lactic acid fermentation occurs
Glucose enters the cell by facilitated diffusion
carb metabolism
Enters the cell via channel protein
No energy required
- Glucose is immediately phosphorylated to glucose-6-phosphate (G6P) (carb metabolism)
This is a nonreversible reaction
This causes the concentration of (unphosphorylated) glucose outside the cell will always be higher than that inside the cell
-Maintains gradient so glucose will always move into the cell
- Glycolysis (catabolic breakdown of glucose) continues and results in the formation of: (carb metabolism)
2 molecules of pyruvic acid
2 molecules of NADH
Net gain of 2 ATP molecules (4 made, 2 used = 2 net ATP gained)
-By gaining 2 ATP molecules, you can always start the process of glycolysis again
(carb metabolism)
- If oxygen is present, oxidative phosphorylation occurs
- If oxygen is not present, lactic acid fermentation occurs —?
Lactic acid is a waste product of fermentation, but can also be used as a source of energy is some places in the body
Ex: the heart
Oxidative Phosphorylation
Pyruvic acid is converted into acetyl-CoA in the mitochondria
-CO2 and NADH are also generated
Acetyl-CoA enters the Krebs cycle
-The Krebs cycle generates 2 CO2, 2 NADH, 1 FADH2, and 1 ATP
Reduced Krebs cycle coenzymes enter the electron transport chain (ETC)
Electrons moving throughout the ETC are used to move hydrogen ions across the plasma membrane
Movement of hydrogen across ATP synthase allows for the phosphorylation of ADP into ATP
-ETC generates H2O and 34 ATP
In carb metabolism all carbs must be turned into what?
All carbohydrates must be turned into glucose before any of this process can occur
Excess glucose
High ATP levels stop glycolysis
-When ATP is high, glucose is converted to glycogen instead of being phosphorylated to G6P
Glycogenesis occurs
-Glucose is converted into glycogen
Glycogen is stored until energy is needed
Low glucose
Glycogenolysis occurs
-A drop in blood glucose leads to the conversion of glycogen into glucose
Gluconeogenesis
formation of glucose from non-carbohydrate sources
Insufficient glucose availability prompts the conversion of glycerol and amino acids into glucose
-Lipids (glycerol) are targeted as an energy source before proteins (amino acids)
Occurs in the LIVER
LIPID METABOLISM
- Absorbed lipids are broken down into glycerol and fatty acids
- We absorb neutral fats - Glycerol is converted to glyceraldehyde phosphate
- Glyceraldehyde phosphate is converted to pyruvic acid in glycolysis
- Pyruvate (pyruvic acid) enters the Krebs cycle - Fatty acids broken into acetic acid in mitochondria
- Acetic acid fuses with CoA to form acetyl-CoA
- Acetyl-CoA enters the Krebs cycle
In lipid metabolism the body will…
utilize carbs as a source of energy before fats are utilized as a source of energy
Excess Lipids (Lipid Storage)
High ATP and glucose levels trigger conversion of glycerol and fatty acids into triglycerides for storage in adipose tissue
Low Energy, High Fats
Lipolysis occurs when energy is needed and no carbohydrates are present
-Break down of triglycerides (lipids) into glycerol/fatty acids to enter the lipid metabolism system
Protein metabolism
-Amino acids deaminated Amine group leaves the amino acid Amine group becomes ammonia Ammonia forms uric acid Uric acid forms urea Urea is excreted
-Deaminated molecules are converted into pyruvic acid or Krebs cycle intermediates
Excess proteins
High ATP levels cause pyruvic acid formed through deamination to be converted back to glucose
-This glucose cannot be converted back to proteins, but can be stored as glycogen
Hormones control protein synthesis on ribosomes
-Steroid hormones turn on protein production
Energy gained per molecule order
Fats (lipids) > carbohydrates > proteins
