Carbohydrates Flashcards
What are Carbohydrates made up of?
- carbon
- hydrogens
- oxygens
Simple Carbohydrates include what 2 types?
- Disaccharide
- Monosaccharide
Monosaccharide means how many?
- one molecule
- 1 carbohydrate molecule
Most sugars are what kind of simple carbohydrate? Disaccharide or Monosaccharide?
- Disaccharide
Two monosaccharides clump together to create a what?
- Disaccharide
- simple
Can monosaccharides be made into a smaller part?
No, they are as small as they can get.
The 3 monosaccharides we have are ..
- galactose
- glucose
- fructose
What is the most important (carbohydrate) monosaccharide fuel source in human cells?
- Glucose
- Diabetes patients: blood glucose levels aka blood sugar
Lactose is a disaccharide and found in what?
Dairy
Fructose is the most abundant sugar found in US food supply.
- cheap
- easily dissolvable
- sweetest sugar/carb
- naturally in fruit and honey (sweetness)
Disaccharides, because they are 2 molecules are too large to pass cell membrane by themselves or by …?
Cell diffusion
Disaccharides need to be broken down during digestion where?
- small intestine
What two mono. create the lactose disaccharide?
- Galactose
- Glucose
What two mono. create the maltose disaccharide?
- 2 Glucose molecules
What two mono. create the Sucrose (fruits, veggies, table sugar) disaccharide?
- Glucose
- Fructose
Complex carbs are aka?
- Polysaccharides (many)
- chain of monosaccharides
What are the 3 types of polysaccharides? Which of them have branching/straight? Which of them have coiled chain?
- Glycogen (branching, coils)
- Starch (branching, coils)
- Fiber (straight, straight chain )
Fiber can be classified as what 2 categories?
- Soluble
- Insoluble
What properties are responsible for the different arrangements of monosaccharides to create poly.?
- type of carbohydrate
- properties
What are the 4 properties that can make up/categorize a polysaccharide?
- length (long), how many mono are linked together
- extent of the branching
- extent of folding/compactness
- straight or coiled chain
More in-depth about Glycogen
- Storage form of glucose in animals and humans
- stored in 2 places (liver, skeletal muscle)
- humans 500grams
— 100g in liver
— 400g in skeletal muscle (depends on sex, training status (endurance), and quantity of muscle you have
How many grams does the human body store glycogen? What is liver/skeletal muscle?
- 500 g
- liver: 100g
- muscle: 400g
The branches in glycogen which is found in liver and muscle, helps with what for the body?
Rapidly breaking down of glucose when the body needs it.
When consuming carbs you get them from what 2 carbohydrates?
- starches
- fiber (cellulose)
Startches and fiber are found where?
- fruits
- veggies
Starch is what?
Storage form of glucose in plants
Where is fiber found?
In most plant, foods
Fiber makes up what part in plants?
Cell walls, plant cells
True or False : Fiber IS digestible. Why/why not?
False
- Because links that link glucose to another cannot be broken down by the human body
- causing us to not gain much fiber
Starches and fiber are made up of what?
Glucose
Glucose is made in plants via what system?
Photosynthesis
Glucose in plants through process of photosynthesis. What happens after this?
Glucose is converted into chemicals that makes cellulose in which makes cell walls.
What is the most important fuel source in humans?
Carbohydrates
True or False : Glucose can be converted to start by photosynthesis.
True
- if wants to store glucose it is stored as starch and if the plant needs glucose it converts starches back to glucose
Glucose is broken down to be used as a form of energy through the process of respiration in plants
-Starches and fiber are made up of glucose (plants)
What is the STORAGR form of glucose, in humans and animals?
Glycogen
What is the recommended carb intake we should consume in a day?
130 g/day needed for a healthy adult
What is the acceptable macronutrient distribution range for carbs?
45-65% of total calorie intake and 45-65% of carbs in your whole diet that good to maintain a healthy lifestyle
Where odes carb digestion and absorption begin?
Mouth with mechanical digestion (teeth/chew) and chemical digestion (water, salts, mucus, and different enzymes)
What is the enzyme that breaks down food and the polysaccharides in the food down into oligosaccharides, disaccharides, and monosaccharides?
Salivary amylase
- goal is to break into smaller parts
What other roles/protection does saliva have for teeth?
- Protects teeth, lining of mouth, esophagus
- moistens our food to allow it to go down esophagus
- mixes with food to make chyme = moves from mouth to esophagus (very strong muscle)
- moves down esophagus by peristalsis (rhythmic muscle contraction) longitudinal, circular, and diagonal muscles allow for further mechanical digestion of food to stomach
- once enters stomach and esophageal sphincter which keeps food from going back up (barfing) opens
- once in stomach food first interacts with hydrochloric acid
1.Inactivates salivary amylase
2.Kills pathogens in our foods (bacteria, funguses avoiding getting us sick) - Stomach made of smooth muscle and contracts in longitudinal, circular, and diagonal motions contributing to mechanical digestion by peristalsis
What is the step by step path of carb digestion and absorption?
- mouth
- stomach
- esophageal sphincter
- pyloric sphincter
- pancreas through pancreatic duct
- small intestine
What is the pancreas and what does it do?
It acts as a exocrine gland, tissue or organ
- Makes substances like sweat tears, saliva and releases it to a specific area/anatomical surface place of body and RELEASES them
–> remeber can act as endocrine and exo
What are the 4 enzymes that are in the pancreas that help break down polysaccharides into smaller parts and then are released through the pancreatic duct?
- Pancreatic amylase
- Maltase
- Sucrase
- Lactase
What does pancreatic amylase do?
Breaks down starches into sugar
What does Maltase do?
Breaks maltose into 2 glucose molecules
What does sucrase do?
Breaks sucrose into 1 fructose and 1 glucose molecule
What does Lactase do?
Breaks lactose into galactose and 1 glucose molecule
What do enzymes combine with in the duodenum in the small intestine and goes through the rest of the small intestine?
Chyme
How many parts does the intestine have? What are they called?
3
- Duodenum
- Jejunum
- Ileum
Where in the small intestine does most absorption happen and is connected to the stomach?
Duodenum
How does chyme move through the 3 parts of the small intestine?
Peristalsis, and gets to the small intestine in about 3-4 hours
Small intestine is about 20 ft long and has lots of surface area ( unfolded and is the size of a football stadium) and has large circular folds that also increase surface area, allows what?
Absorbs a lot of nutrients that are needed for the human body
In large folds, “villi” which are fingerlike projections that each contain a capillary and lacteal inside of it (capillary of lymphatic system) that helps increase surface area as well to absorb nutrients.
What are on top of “villi” and what do they do?
Microvilli
- tiny projections of the mucosal cell membrane often refereed to as the brush border
- cells are epithelial cell which increases surface area for nutrients
While chyme is moving through stomach and through the small intestine absorption is occurring (goal of digestion is the get polysaccharides to smaller form of monosaccharides which are the only ones that can be absorbed because they are the smallest) so that’s why polys need to be broken down into mono (3 dif. ones)
Where does “fructose” in chyme get absorbed? How?
Through mucosal cell in the small intestine
- By Facilitated diffusion
What is “facilitated diffusion” for fructose?
When water soluble molecule uses a channel protein to pass down a concentration gradient into mucosal cell.
- Fructose goes through a glutfy transporter to enter mucosal cell of small then enters cap then blood
Once fructose is in the blood, it can be used as an energy source.
- Liver to make ATP
–> MAJORITY or it gets converted to glucose mainly in the liver - some fructose can be converted into fat
How does “galactose and glucose” in chyme get absorbed and enter the cell?
Active Transport
What is “active transport” for galactose and glucose?
Protein pump uses ATP energy to move molecules (galactose and glucose) across concentration gradient into cell of S.I
What transporter does galactose and glucose move through to get to the cell capillaries and then into the blood stream?
SGLT1 transporter (sodium glucose transport protein
What happens when galactose and glucose get into the blood and then the liver?
Gets converted to glucose intermediate used as a energy source or stored as glycogen
Remainder (unabsorbed) portion of chyme is moved by peristalsis into the large intestine.
–> Fiber is partially broken down by bacteria to form short-chain fatty acids and gas
–> Remaining fiber is excreted in the feces
–> Makes way to large intestine where can be partially broken down through gut microbiome
———Can partially break down into shorter chains of fatty acids into gas (fart)
———Remainder is just ultimately pooped out
What is “post prandial blood glucose”?
Period from when you first eat your meal to 4 hours after
Are you blood glucose levels after a meal “dependent” or “independent” on the meal that you eat?
Dependent
What is the “glycemic index”?
Ranking of how a food affects blood glucose relative to an equivalent amount or carbs from a reference food
1.glucose drinks
2. white bread (high in glycemic carbohydrate)
–> when get a high glycemic index food=more quickly absorbed and metabolized in the body
–> there is going to be a high curve in blood glucose concentration bc to high glycemic food
–> SLOW: has a smaller curve = lower and slower response to glucose
White bread is high in glycemic carbohydrate food which means?
It is quickly absorbed and metabolized in the body
–> there is going to be a high curve in blood glucose concentration bc to high glycemic food
–> SLOW: has a smaller curve = lower and slower response to glucose
What is “glycemic response”?
Measures how quickly and how high blood glucose levels rise after carbs consumption
–> lots of glucose entering the blood very fast
What is the “glycemic load”?
Compares the effect of typical portions of food on blood glucose.
–> 1. Considers of the quality and quantity of glucose intake
–> 2.Higher the load the higher the index
Does co-ingestion of protein and fast slow digestion and movement of chyme or speed it up?
Both slow
What are the 2 fates of glucose in the body when blood glucose levels rise?
- Stored as glucose int he skeletal muscle or liver if not being used
- Glucose is used as an energy source to make more ATP
What two ways can glucose be stored in the skeletal muscle of liver? How are they able to?
- Glycogenesis
- Lipogenesis
–> it costs energy ATP
What is “glycogenesis”?
Glycogen synthesis from glucose
Steps of Glycogenesis …
1.ATP donates a phosphate to glucose to form glucose 6 phosphate
2.Through additional enzymatic reactions glucose 6 phosphate becomes uridine diphosphate-glucose (UDP glucose)
3.The enzyme glycogen synthase catalyzes/convert UDP-glucose to attach to one end of an existing glycogen chain
What is the key enzyme for glycogen to be made and another glucose to be added to an already existing glycogen chain?
Enzyme glycogen synthase
What is “lipogenesis”?
Formation of fat from glucose
1.Acetyl-coA is mainly generated by combustion of glucose, fatty acid, and proteins
–> Is synthesized into fatty acids primarily in the liver
2.Contributes 1-3% of the total fat balance in humans consuming a typical diet (small amount)
Glucose is utilized as an energy source for ATP.
- If body needs to regenerate ATP then glucose is utilized as an energy source for cellular metabolism
What is the energy currency of the human body?
ATP, and allows for all cellular actions
ATP is NOT constantly being regenerated in the body.
TRUE or FALSE
False
–> IS allows being regenerated
What are the 3 ways that glucose is used as an energy source and its benefits.
- Protein Sparer
- Fuel for CNS
- Prevents Ketosis
How is glucose used as an energy source as a “protein sparer”?
Because there is no storage form for protein (more skeletal muscle mass synthesis more protein there) ….. glucose breaks down amnio acids in skeletal muscles to make ATP
How is glucose used as an energy source in being “fuel for the CNS”?
- Because CNS depends highly on glucose as a fuel source glucose to resynthesize ATP
- Brain and spinal cord, RBC, few cells in our eyes
- Certain tissues in our body that can only resynthesize ATP using glucose
- When we consume a high glucose meal it is a benefit to those that only relies on glucose
How is glucose used as an energy source to “prevent ketones”?
- Ketones or ketone bodies acidic molecules produced by fat when glucose is not present ….breakdown in which there is increased production when carbs are no available to cell
2 . Constantly happening - If on low carb diet/starving = more fat being broken down in body as an energy source
- Ketones are being produced in an excessive amount
- They are acidic molecules
—-> When excess amounts in blood it can alter/decrease your pH in blood = acidic
What is “ketoacidosis”?
Metabolic state of ketone bodies formed by break down in fat in body = eventually can be fatal
What are the 2 endocrine hormones of the pancreas that regulate blood glucose?
- Insulin
- Glucagon
What kind of gland is the pancreas when managing/making horomones?
Endocrine gland
- an organ that makes hormones that are released directly into the blood and travel to tissues and organs all over the body
What is “insulin” and what does it do?
A hormone that regulates glucose entry into all tissues except the brain
–> (released to external space around the pancreas eventually getting into he bloods to have systemic affects on the tissues throughout the body)
What is “glucagon” and what does it do?
Hormone that works in the liver to promote the formation of new glucose
Where are both insulin and glucagon made?
Pancreases islets of Langerhans (endocrine aspect of the pancreas)
What 2 cells are the pancreases islets of Langerhans made of?
- Alpha cells
- Beta cells
What do alpha cells do?
Synthesizes glucagon and promotes new formation of glucose in the liver
What do beta cells do?
Synthesize insulin goal to regulate all glucose to all parts of body except of brain
–> happens for every part of the body except for CNS and focuses on skeletal muscle
What is on skeletal muscle membrane to help with insulin?
Insulin receptors
What happens when you have higher glucose blood levels?
Pancreases releases and synthesizes more insulin because it is needed to get glucose to parts of the body.
What are the steps when the pancreas releases insulin to eventually deliver glucose to the tissues of the body?
Step 1: insulin secreted by pancreas…. As insulin is circulating throughout the blood it binds to insulin receptor on 3 main tissues (all 4 steps happen in these 3 tissues)
–> Liver: insulin decreases blood glucose by supporting glycogen synthesis
–> Skeletal muscle: insulin decreases blood glucose by supporting glucose use and storage as glycogen
–> Adipose tissues also help with bring glucose levels back down to normal: have insulin receptors on them and insulin decreases blood glucose by stopping the break down of fat for energy and supporting glucose uptake/storage as triglycerides
………Signals to stop breaking down after you didn’t eat for a while and your body starts breaking down fat, but once you do eat, this process tells the body to stop breaking down excess fat
Step 2: binds and causes signal transduction cascade = things are turned on and tells transport protein (GLUT-4) to move the cell membrane
Step 3: GLUT-4 is deep in tissue not very close to cell mem. so moves by exocytosis to cell membrane
Step 4: then allows glucose to get into cell then eventually to tissues of the body
–> All need to occur to bring down increased blood glucose levels after a high carb meal and glucose levels rise
–> Takes about 2-4 hrs to get back to normal and Also post-prandial state
Maintaining fasting blood glucose is what?
Glucagon
What is the “normal fasting blood glucose” level range?
70-99.9 mg/dL
- greater than 120 is considered pre-diabetic and higher than that is severe diabetes
What are the steps to get low blood glucose levels back to normal?
Having decreased blood glucose
1. pancreas secretes glucagon
2. glucagon works in the liver to break down glycogen to glucose into the blood
–> or liver stimulate glucose synthesis (gluconeogenesis) and can be synthesized from substrate like fatty acids, glycerol, amnio acids, and lactate
3. increase in blood glucose levels to maintain that normal glucose percentage
