carbohydrates W2 Flashcards
what are carbohydrates main function
to provide energy
how much energy (cal) does 1 g of carbohydrates produce
4.2 cal
what is the preferred fuel source of the nervous system
glucose
what are the structural functions of carbohydrates (2)
DNA/RNA
linked to proteins and lipids
carbohydrates are classified according to:……
size
primary monosaccharides (3)
glucose
fructose
galactose
where is glucose found in diet (1)
fruit and vegetables
where is fructose found in the diet (3)
sugar
honey
fruit and veg
where do you find galactose in the diet (1)
milk sugar
primary disaccherides (3)
sucrose
lactose
maltose
how are disaccherides formed
monosaccerides join together with weak covalent bonds via dehydration synthesis
what is the name of the weak covalent bonds that hold monosaccherides together to form disaccherides
glycosidic bond
between which parts does the glycosidic bond form in a disaccheride
hydroxyl group (OH)of C1 of a monosaccheride and the hydroxyl group of a second monosaccheride (only H)
ratio of CHO in a monosaccheride
(1:2:1)
what are the key hexose sugars(6C)(3)
glucose
fructose
galactose
what are the key pentose sugars (5C) (2)
deoxyribose
ribose
chemical formula of hexose monosaccherides
C6H12O6
monosaccherised have a ring structure, given that the PH is…
7
chemical formula of common disaccherides
C12H22O11
where is the dietwould you find sucrose (1)
table sugar, and anything that has it
where in the diet would you find lactose(3)…not (1)
lactose is milk sugar, therefore in milk products eg
milk
yoghurt
icecream
not butter
where in diet would you find maltose (2)
beer and liquor
what is alpha formation
trans to C5 (right OH facing down)
what is beta formation
Cis to C5 (right OH facing up)
> 6 monosaccerides=
polysaccheride
2-6 monosaccherides=
Oligosaccheride
what is starch
the stored form of carbohydrates in PLANTS
what is fibre
part of cell wall of plants
can fibre be digested by humans
no
what is glycogen
stored form of carbohydrates in ANIMALS
polysaccherides in the diet (3)
grains
legumes
root vegetables
starch is …..polumers
glucose
what is the major source of carbohydrates in our diet(1)
starch
what do plants store glucose as (2)
amylose
amylopectin
structure of amylose (shape and linkage)
linear
Alpha 1-4
structure of amylopectin (shape and linkage)
branched
Alpha 1-4
branch: Alpha 1-6
every 24-30 residues
two structures of polysaccherides
linear
branched
what enzyme aids in the digestion of amylose and amylopectin
amylase enzymes
where is the amylase enzyme found(2)
mouth and small intestine
two types of fibre
soluble and insoluble
what is cellulose
insoluble fibre
name the primary insoluble fibre
cellulose
where is cellulose found
in all plant foods, it is the main structural component of the plant cell wall
cellulose structure and linkage
glucose molecule chains with Beta 1-4 linkages
how is cellulose digested
it isnt, it adds to bulk of stool
examples of soluble fibre (4)
some hemicellulose
pectin
gums
Beta glucans
what happens to soluble fibre in digestive process
is soluble therefore it forms viscous gel
what happens to the viscous gel that soluble fibre forms in the gut
bacteria in colon ferment the gel forming short fatty acid chains which can be absorbed and used for energy production
advantages of glycogen (3)
- insoluble
- readily converted back onto glucose in liver
- readily converted to energy (liver and muscle)
glycogen structure (1) and linkages (3)
-highly branched glucose polymer
-Alpha 1-4
-branches: Alpha 1-6
branches every 12 residues
advantages of glucose
water soluble—> free glucose in bloodstream
-can enter ALL cells and be used for energy production
which cells only use glucose (2)
brain and RBC
what transports glucose into skeletal muscle cells
gluT 4 transporters
what transports glucose into liver cells
gluT 2 transporter
skeletal muscle and adipose tissue require ……. to increase cell’s uptake of glucose
insulin
how does insulin affect a cells glucose uptake
insulin binds to receptor, and signals for more gluTs to move to cell membrane and increase uptake of glucose
is glucose osmotically active
yes
glucose is osmotically active, what can this cause
dehydration
what can chronically high blood glucose levels lead to
non-specific binding of glucose to proteins
hihg blood glucose levels –> non-specific binding of glucose to proteins is a common problem in
type 2 diabetes
what are the two main hormones involved in blood glucose regulation
insulin and glucagon
where is glucagon released from
alpha cells of pancrease
glucagon is released from…. and travels to….
pancreas
liver
insulin is release from
beta cells of pancreas
insulin travels from …. to…..
pancreas
skeletal muscle
liver
adipose tissue
insulin is released in response to…..
high blood glucose levels
glucagon is released in response to …..
low glucose levels
glucagon is released, this causes a …..in blood glucose levels
increase
insuling is released, this causes an…..in blood glucose levels
decrease
health benefits of fibre (4)
- toxins have less contact with body
- binds with carcinogens
- eat less
- binds to cholesterol
risks of low fibre diet (6)
- constipation
- haemorrhoids
- irritable bowel syndroe
- obesity
- coronary heart disease
- colon cancer
