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Macromolecules Flashcards

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AP® Biology flashcards Biology 101 flashcards
1
Q

What are macromolecules?

A

large molecules composed of thousands of covalently linked atoms
- structure and function are inseparable

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2
Q

What is a polymer?

A

a long chain-like molecule consisting of many similar or identical building blocks linked together by covalent bonds

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3
Q

What is a monomer?

A

small building-block molecules

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4
Q

Synthesis of a polymer

A

monomer form larger molecules by bonding together through the loss of a water molecule

= condensation / dehydration reaction

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5
Q

Breakdown of polymer

A

polymers are disassembled to monomers by hydrolysis
- water is added

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6
Q

How is the diversity of polymers achieved?

A

-> arrangement of the monomers into polymers

all organisms share the same limited number of monomer types (40-50 types)

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7
Q

what are monosaccharides?

A

simple sugar
- most common: Glucose
- carbonyl group and many hydroxyl groups
- classified by the location of the carbonyl group (aldose or ketose)
- size of carbon chain (3-7)
- spatial arrangement of their parts around asymmetric carbons
- many form rings in aqueous solutions
- serve as major fuels in cells and raw material for building molecules

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8
Q

What is the difference between aldose and ketose?

A

carbonyl group is at the end of the skeleton in aldehydes
in the middle in ketones

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9
Q

What are disaccharides?

A

two monosaccharides joined by dehydration reaction
- most common is sugar (glucose+fructose)
- maltose: 2 glucose
- glycosidic linkage

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10
Q

What kind of bond has maltose?

A

1,4 glycosidic linkage

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11
Q

What kind of bond has sucrose?

A

1,2 glycosidic linkage

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12
Q

What are polysaccharides?

A

macromolecules, polymers of sugar
- storage and structural functions

structure and functions are determined by its sugar monomers and the positions of glycosidic linkages

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13
Q

What are the storage polysaccharides?

A
  • plants use starch
    -> excess starch is stored as granules within chloroplasts and other plastids
  • animals use glycogen
    -> stored mainly in liver and muscle cells

both consist of glucose monomers, but have different spatial arrangements

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14
Q

What is starch made of?

A

most are linked by 1,4 linkages -> helical

  • amylose, unbranched
  • amylopectin, branched polymer with 1,6 linkages at branch points
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15
Q

What is the structure of glycogen?

A

branched polymer with 1,6 linkages at branch points

more branched than amylopectin

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16
Q

What are structural polysaccharides?

A

cellulose:
- in though walls of plant cells
- polymer of glucose
- beta-glucose -> straight (alpha glucose in starch -> helical)
-> can be stacked closer together
- 1,4 linkages in beta glucose monomers

about 80 cellulose molecules associate to form a microfibril, the main architectural unit of plant cell wall

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17
Q

What is the structure of cellulose?

A
  • cellulose is never branched
  • some hydroxyl groups on its glucose monomers are free to hydrogen-bond with the hydroxyls of other cellulose molecules lying parallel to it
    -> grouped together into microfibrils
  • microfibrils are strong building material for plants and important for humans -> major constituent of paper and the only component of cotton
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18
Q

how is cellulose digested? in humans

A
  • enzymes can digest starch by hydrolysing alpha-linkages, but cant hydrolyse beta linkages in cellulose (they have distinctly different shapes)
  • humans can not digest cellulose
  • cellulose passes through digestive tract as insoluble fiber -> stimulates the secretion of mucus, which aids the passage of food through the tract (ballaststoffe)
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19
Q

how is cellulose digested in herbivores, fungi?

A
  • herbivores (cows, termites) have symbiotic relationships with microbes that have enzymes to digest cellulose into glucose in their stomach
    (prokaryotes and protists)
  • eg in cows, the microbes hydrolyse cellulose in hay and grass converting into nutrients
  • some fungi also digest cellulose -> aid in the recycling of chemical elements
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20
Q

What are lipids?

A

the only biomolecules that do not form polymers

  • hydrophobic, due to the main component being hydrocarbon chains
  • most important types:
    fats, phospholipids and steroids
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21
Q

What are fats made of?

A

glycerol:
3 carbon alcohol with -OH group at each carbon

fatty acid:
-OH group attached to a long carbon skeleton (16-18C)

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22
Q

What is a triacylglycerol / triglyceride?

A

3 fatty acids joined to glycerol by an ester linkage

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23
Q

Why are fats hydrophobic?

A

mainly because of the relatively non-polar C-H-bonds in the hydrocarbon chains in fatty acids

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24
Q

What are the differences in fatty acids?

A

vary in length (number of carbons)
very in number and locations of double bonds

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25
Q

What are saturated fatty acids?

A

have the maximum number of H-atoms and no double bonds

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26
Q

What are unsaturated fatty acids?

A

have minimum one double bond

cis-double bond causes bending in structure

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27
Q

animal fats

A

are saturated and solid at room temperature
-> can be packed tightly due to their flexibility

28
Q

plant and fish fats

A

unsaturated and liquid at room temperature
- kinks due to cis double bonds do not allow them to be packed tightly

29
Q

What are hydrogenated vegetable oils?

A

unsaturated fats that have been synthetically converted to saturated fats by adding hydrogen

30
Q

What is atherosclerosis?

A

plaque build up in the walls of blood vessels, causing inward bulges that impede blood flow and reduce resilience of vessels

  • hydrogenating vegetable oils also creates unsaturated fats with trans double bonds -> these trans fats may contribute more than saturated fats to cardiovascular disease
31
Q

What is hydrogenation?

A

process of converting unsaturated fats to saturated fats by adding hydrogen

  • also creates unsaturated fats with trans double bonds -> trans fats
32
Q

What is the major function of fats?

A
  • energy storage as hydrocarbons are rich in energy (1g of fat stores twice as much as 1g of polysaccharides)
  • in adipose cell
  • adipose tissue also serve as cushions for vital organs and insulate the body
33
Q

What is the structure of phospholipids?

A

2 fatty acids + phosphate attached to glycerol

fatty acids (tail) is hydrophobic, head (phosphate) is hydrophillic

34
Q

What happens to phospholipids in aqueous solutions?

A

assemble to a bilayer because of their hydrophobic and hydrophillic traits

35
Q

Steroids

A

lipids with characteristic carbon skeleton consisting of 4 fused rings

  • vary in their chemical groups attached to the rings

Cholesterol: component in animal cell membrane and precursor of some hormones
- high levels are risk of cardiovascular disease

36
Q

What are proteins?

A

= biologically functional molecules that consists of one ore more polypeptides
-> coiled or folded into a specific 3D structure

  • make up more than 50% of the dry mass of most cells
  • functions include transport, enzymes, structure, communication, storage, movement, immune system
37
Q

What is an enzyme?

A

catalyse a reaction, without being altered by the reaction
- can perform their function repeatedly
- active site for the substance

38
Q

What are polypeptides?

A

unbranched polymers built from the same set of 20 amino acids
- peptide bond

39
Q

What are amino acids?

A

organic molecules with a carboxyl and amino group connected to a central alpha carbon

  • have different properties due to different side chains (r groups)
  • functional r group determine the unique characteristics of a particular amino acid -> affects its functional role in a polypeptide

-> non polar side chain: hydrophobic
-> polar side chain: hydrophillic (acidic due to carboxyl group, basic due to amino group)

40
Q

how are the amino acids linked together?

A

by peptide bonds in dehydration reaction

  • carboxyl group + amino group
41
Q

How is the function of a protein determined?

A
  • the amino acid sequence of a polypeptide determines the 3D structure of the protein
  • the protein’s structure determines its function -> the function of a protein usually depends on its ability to recognise and bind to some other molecule
42
Q

Primary structur

A

unique sequence of amino acids in a polypeptide

43
Q

secondary structure

A

folding or coiling of the polypeptide into a repeating configuration
- stabilised by H-bonds between atoms of repeating parts of the polypeptide back bone
- alpha helix and beta-pleated sheets

44
Q

tertiary structure

A

3D shape of polypeptide
- interactions (h-bonds, van der waals, ionic bonds, hydrophobic interactions) between amino acids and r groups
- disulfide bridges ( covalent bonds) may reinforce the structure
- ‘ the sentences’
- stabilised by side chain interactions

45
Q

quaternary structure

A
  • association of multiple polypeptides, forming a functional protein
  • results from combination of two or more polypeptide subunits
46
Q

sickle cell disease

A
  • change in primary structure -> a single amino acid substitution
  • inherited blood disorder
  • hemoglobin tends to crystallise, deforming some of the cell to sickle shape
47
Q

What are the factors affecting protein structure?

A

-> physical and chemical conditions of its environment
- pH
- Temperature
- salt concentration

48
Q

What is denaturation?

A

protein unravels and loses its natural shape
-> protein is biologically inactive

49
Q

What are chaperonins?

A

protein molecules that help the proper folding of other proteins

misfolding could lead to alzheimers, parkinsons

50
Q

What are the methods to determine a protein’s 3D structure?

A
  • X ray crystallography
  • nuclear magnetic resonance (NMR)
  • cryogenic electron microscope (cryo EM)
  • bioinformatics
51
Q

what is a gene?

A

a unit of inheritance in DNA

52
Q

What is DNA?

A
  • 2 strands of polynucleotides spiraling around forming a double helix
  • backbones run in opposite 5’->3’ direction -> antiparallel arrangement
  • strands held together by h-bonds between the bases (a+T, G+C)
  • sugar phosphate backbone on the outside, nucleotide base on the inside
  • semiconservative replication
53
Q

Watson and Crick

A
  • introduced the double helical model for DNA
  • Franklins Xray crystallised images helped watson to deduce the helical shape, the width of the helix and the spacing of the nitrogenous bases
  • structure revealed its function
54
Q

What is RNA

A

single stranded
- complementary pairing might occur between 2 RNA molecules or between parts of the same molecule
- Uracil instead of Thymine
- RNA are variable in form

55
Q

what is a nucleotide

A
  • nitrogenous base
  • pentose sugar
  • phosphate group
56
Q

what is a nucleoside

A
  • nitrogenous base
  • pentose sugar
57
Q

what is the nitrogenous base?

A
  • one or two rings of carbon with nitrogen atoms
    -> N-atoms take up H+, acting as bases
  • pyrimidines: cytosine, thymine and uracil
    have 6 C rings
  • purines: adenosine and guanine
    have 6 + 5 rings fused
58
Q

What is the pentose sugar?

A

desoxyribose in DNA and ribose in RNA

desoxyribose lacks o-atom at the 2nd carbon of the ring

59
Q

phosphodiester bind

A

covalent bond between the OH group of 3’ C of sugar and phosphate group of 5’ C

-> creates the backbone of sugar-phosphate units with nitrogenous bases as attachments

60
Q

What are the ends of the polynucleotides?

A
  • 5’ end with phosphate group
  • 3’ end with OH group of sugar
61
Q

DNA and proteins as tape measures of evolution

A
  • molecular comparison in molecular biology help biologists sort out the evolutionary connections between species
  • comparing the amino acid sequence of proteins between different species
    -> the more related the two species are, the more similar the amino acid sequence of their proteins is
62
Q

Bioinformatics

A

use computer software and other computational tools to deal with the data resulting from sequencing many genomes

63
Q

genomics

A

analysing large sets of genes or even comparing whole genomes of different species

64
Q

proteomics

A

similar analysis of large sets of proteins including their sequences

65
Q
A

Biology (6 decks)

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