Lecture 15 Flashcards Preview

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Flashcards in Lecture 15 Deck (27)
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1
Q

monosacs- two types

A

aldoses and ketoses

at least two hydroxyl
groups (CH2O)n

2
Q

aldoses

A

carbonyl group comes at the end of the chain and thus represents an aldehyde group

3
Q

ketoses

A

carbonyl group occurs within the chain and hence represents a ketone group

4
Q

enatiomers

A

stereoisomers that are nonsuperimposable mirror images of eachother

5
Q

diastereomers

A

Diastereomerism occurs when two or more stereoisomers of a compound have different configurations at one or more (but not all) of the equivalent (related) stereocenters and are not mirror images of each other.

6
Q

Carbohydrates

A

Primary energy source in bread, rice and pasta

  • They do not catalyze reactions.
  • They do not replicate.
  • They serve as signals on cells.
  • They are important fuels.
  • They taste good.
7
Q

Glyceraldehyde

A

is the smallest aldose

8
Q

D or L more common?

A

D

9
Q

Epimers

A

differ from each other at just one asymmetric carbon

10
Q

Dihydroxyacetone

A

is the smallest ketose

• No asymmetric carbons.

11
Q

Ketoses

A

have 1 fewer asymmetric carbons than aldoses

Ketoses often use the same root names as aldoses but with a“ul” included in the middle of the name.

12
Q

anomeric

A

The carbonyl carbon becomes the “anomeric” carbon

α means opposite CH2OH (carbon 6)

β means same side as CH2OH (carbon 6)

13
Q

Glycosidic bonds

A

form when an anomeric carbon reacts with an alcohol

14
Q

galactose and glucose relationship

A

epimers

15
Q

non-reducing

A

This cannot form a free aldehyde or ketone

so it is called a non-reducing sugar

16
Q

Maillard Reaction

A

Reaction of reactive carbonyl of the open forms reducing sugars with nucleophilic amino groups of amino acids at high temperature to
produce a complex mixture of substances.

17
Q

Hemoglobin A1c:

A

N-fructosyl-valine Hemoglobin

High levels of HbA1c are a
reliable indicator of diabetes.

18
Q

Polysaccharides

A

Cellulose, chitin, glycogen, starch

19
Q

cellulose

A

glucose+ glucose

Wood, white cotton and paper are almost pure cellulose.
We cannot digest cellulose. Estimated 1015 kg of
cellulose is synthesized and degraded on earth
annually!!

20
Q

EM of cell wall of green algae..shows rigid long cellulose fibrils.

A
Who can digest cellulose?
•Cows (rumen full of bacteria)
•Termites (endogenous and bacterial
cellulase)
•Biofuel companies (make cellulosic ethanol starting with fungal cellulases or acid treatment)
21
Q

chitin

A

next to cellulose, chitin is the second most abundant polysaccharide in nature

22
Q

amylose

A

this type of helix cannot form when there are branches

23
Q

cellulose

A

β-D 1,4

24
Q

Unbranched Starch – α amylose

A

Starch is insoluble in water and must be broken down by pancreatic amylases.

25
Q

amylopectin

A

can be up to 10^6 glucose residues
α (1–>6) branch point
(one every 24-30 residues)

26
Q

HIGH FRUCTOSE CORN SYRUP

A

cornstarch ~7-% amylopectin –> (α-amylase) —> Oligosaccharides of glucose —> (glucoamylase) –> glucose –> (glucose isomerase) —> glucose (42%) & fructose (55%)

“HFCS 55”

27
Q

Glycogen

A

stored glucose in muscle and liver.
More branched than starch.
Glucose can be released starting at non-reducing ends.

(one every 8-14 residues)