Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

MCAT Biochemistry > Water, Lipids, Carbohydrates, and Nucleotides > Flashcards

Water, Lipids, Carbohydrates, and Nucleotides Flashcards

You may prefer our related Brainscape-certified flashcards:
MCAT flashcards
1
Q

Hydrogen Bonding

A

Intermolecular bonding between H and F, O, or N. Provides strong cohesive forces between water molecules
Responsible for elevation of boiling point of water

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Hydrophilic

A

A characteristic referring to the tendency of molecules to congregate near and dissolve in water.
Ionic compounds’ negatively charged ends are attracted to partial positive charge of water’s hydrogen and positively charged ends are attracted to partial negative charge of water’s oxygen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Hydrolysis

A

Most macromolecules of living cells are broken apart by this process through the addition of water
Hydrolysis of ATP molecules provides the body’s major source of energy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Dehydration synthesis

A

Reverse reaction of hydrolysis. Two molecules are combined to form a larger molecule and water is formed as a byproduct
Allows formation of bonds that make up biological molecules (peptide, ester bonds)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

ATP Hydrolysis reaction

A

Water serves as nucleophile and attacks the electrophilic phosphoanhydride bond between the beta and gamma phosphates of the ATP molecule.
Gamma phosphate is freed and can be used by a kinase enzyme

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Lipids

A

Low solubility in water and high solubility in nonpolar organic solvents
Nonpolar and hydrophobic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Roles of lipids in an organism

A
  1. Energy storage: long carbon chains
  2. Cellular organization and structure: fats assemble into barriers separating aqueous environments (hydrophobic)
  3. Provision of precursor molecules for vitamins and hormones: can pass easily through cellular membranes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Fatty Acids

A

Lipids that are the building blocks for the most complex lipids
Act as fuel for body, components of cell membranes
Long chains of carbons truncated at one end by carboxylic acid (even Cs, max of 24)
Store more energy than any other molecule (9kcal)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Unsaturated Fatty Acid

A

Contain one or more Carbon-Carbon double bonds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Saturated Fatty Acid

A

Have only single Carbon-Carbon bonds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Triacylglycerol

A

AKA triglycerides or fats and oils
Constructed from 3C backbone called glycerol attached to three fatty acid chains
Function: to store energy, thermal insulation and padding to organism
Found in adipocytes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Sphingolipids

A

Have long chain fatty acid and polar head group, with amino alcohol (Sphingosine) backbone, rather than glycerol
Make up part of cell membrane

Sphingomyelin: phosphate group attached to sphingosine backbone (phospholipid)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Phosphatids

A

Simplest phosphoglycerides.

Glycerol backbone with a phosphate group attached

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Steroids

A

Four-ringed structures
Include some hormones, vitamin D, and cholesterol

Cholesterol: maintains membrane stability and fluidity (precursor for steroid hormones)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Terpenes

A

Sixth class of lipids that are often part of pigments in the body

Includes vitamin A

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Waxes

A

Formed by ester linkage between a long-chain alcohol and long-chain fatty acid

Water-repellant texture

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Eicosanoids

A

12C structures, often considered a fatty acid
Released from cell membrane as local hormones that regulate blood pressure, body temperature, and smooth muscle contraction.

Includes prostaglandins, thromboxanes, and leukotrines.
Aspirin inhibits synthesis of prostaglandins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Lipoproteins

A

Contains a lipid core surrounded by phospholipids and apoproteins
Able to dissolve lipids in hydrophobic core

Move freely in aqueous solutions due to cell

Classified by density; greater ratio of lipid to protein, lower the density

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Major classes of lipoproteins

A

Chylomicrons
Very low density lipoproteins (VLDL)
Low density lipoproteins (LDL)
High density lipoproteins (HDL)

20
Q

Major functions of lipids

A
  1. Phospholipids serve as structural component of membranes
  2. Triacylglycerols store metabolic energy and provide thermal insulation and padding
  3. Steroids regulate metabolic activity
  4. Some fatty acids (eicosanoids) serve as local hormones
21
Q

Phospholipids

A

Lipids with a phosphate group attached
E.g. phosphoglycerides
Glycerol backbone, with polar phosphate group at head and two fatty acids at tail
Amphipathic, suited for cell membrane

22
Q

Glycoliopids

A

One or more carbohydrates attached to 3C glycerol backbone with two fatty acids at tail
Amphipathic
Found in membranes of myelinated cells in human nervous system

23
Q

Adipocytes

A

Specialized cells whose cytoplasm contains almost nothing but triglycerides

24
Q

Types of lipids

A

Fatty acids, Triacylglycerols, Phospholipids, Glycolipids, Sphingolipids, Steroids, Terpenes, and Waxes

25
Q

Carbohydrates

A

Carbon and water fixed in a one-to-one ratio:
C_n (H_2O)_n
Useful for storing energy and providing easily accessible energy to the body
Store up to 4 kcal of energy in C-H bonds
Consistent structure allows stacking in cell

26
Q

Polysaccharides

A

Long chains of carbohydrates formed from linkage of many monosaccharides
Useful for energy storage

Dehydration: forms polysaccharides
Hydrolysis: Breaks down polysaccharides to monosaccharides through addition of water

27
Q

Glucose

A

Most commonly occurring six carbon carbohydrate (hexose)
Accounts for ~80% of carbohydrates absorbed by humans. Almost all digested C converted to glucose by liver or enterocytes (intestinal cells)
Glucose polymerized to polysaccharide, glycogen, or converted to fat when sufficient energy available

28
Q

Glycogen

A

Branched glucose polymer with alpha linkages
Found in all animal cells, but large quantities in muscle and liver cells
Liver can break down glycogen to glucose when needed (regulate blood glucose level)

29
Q

Absorption of glucose

A

Most cells absorb glucose via facilitated diffusion
- Insulin increases this ability

Epithelial cells in digestive tract and proximal tubule of kidney are capable of absorbing glucose against concentration gradient
- secondary active transport down gradient of sodium

30
Q

What happens to glucose absorption without insulin?

A

As insulin increases rate of facilitated diffusion of glucose, affects the uptake of glucose and blood glucose level

Only neural and hepatic cells are capable of absorbing sufficient amounts of glucose via the facilitated transport system

31
Q

Starch

A

Polysaccharides present in animals
Can be amylose or amylopectin
Amylose: branched or unbranched and has same alpha linkages as glycogen
Amylopectin: resembles glycogen, but has different branching structure

32
Q

Cellulose

A

Structural material in plants (polysaccharide) formed from glucose
Composed of beta linkages, stable for plant cell walls
Humans have enzymes to digest alpha linkages, but not cellulose- fiber
Bacteria break beta linkages

33
Q

Nucleotides

A

Important class of molecules, building blocks of genetic material, involved in cell’s usage of energy

34
Q

Three components of Nucleotides

A
  1. Five carbon (pentose) sugar
  2. Nitrogenous base
  3. Phosphate group
    Highly stable sugar with phosphate group can link together to form stable and organized backbone (polar and hydrophilic)
    Nitrogenous bases form weak H bonds to stabilize double helix, but can be separated
35
Q

Four Nitrogenous Bases

A

Adenosine, Thymine, Guanine, and Cytosine

Two H-bonds form between A and T

Three H-bonds form between C and G

36
Q

Purines

A

Guanine (G), and Adenine (A)

Two ring nitrogenous base structure

37
Q

Nucleoside

A

Pentose sugar attached to nitrogenous base

Form nucleotide with addition of one or more phosphate groups to nucleoside

38
Q

Nucleic Acids

A

Polymers of nucleotides

Known as DNA or RNA
Specify production of proteins to allow for expression of genetic traits
Formed by phosphodiester bonds between phosphate group of one nucleotide and 3rd C of pentose sugar of next nucleotide

39
Q

Sugar Phosphate Backbone

A

Formed by phosphodiester bonds between nucleotides

40
Q

In what direction are strands of nucleotides synthesized?

A

Synthesized by DNA polymerase in 5’ to 3’ direction

41
Q

Watson-Crick Model of DNA

A

B Form of DNA: Two strands of DNA lie side by side in opposite 3’ to 5’ direction (antiparallel) bound together by H-bonds between nitrogenous bases, forming double-stranded structure
One spiral for every 10 nitrogenous bases

42
Q

Complementary Strands

A

DNA strands whose bases match up in the correct order

43
Q

RNA

A

Ribonucleic Acid:
1. Carbon number 2 on pentose is not deoxygenated (hydroxyl attached)
2. Almost always single stranded
3. Contains pyrimidine uracil (U) instead of thymine (T)
Can move through nuclear pores

44
Q

Three types of RNA

A 
Messenger RNA (mRNA)
 Ribosomal RNA (rRNA)
 Transfer RNA (tRNA)
45
Q

Important Nucleotides beside DNA

A

ATP (adenosine triphosphate) for energy
Cyclic AMP (cAMP) important component in secondary messenger systems
NADH, FADH are coenzymes involved in Krebs Cycle and electron transport chain

46
Q

Pyrimidines

A

Cytosine (C) and Thimine (T)

One ring nitrogenous base structure

MCAT Biochemistry (11 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions