AP Biology Chapter 5: The Structure and Function of Large Molecules

macromolecules

A very large organic molecule composed of many smaller molecules (chain like molecules)

polymer

A long molecule consisting of many similar or identical monomers linked together by covalent bonds

True or False: Monomers are the building blocks of polymers, and some have their own functions

True

Polymerization

process of making polymers by attaching many monomers together (facilitated by enzymes)

condensation reaction

- connects monomers to other monomers

- two molecules are bonded by the loss of a water molecule

ex: dehydration reaction

dehydration reaction (carbohydrates and protein polymers do this)

each reactant provides a part of a water molecule (a hydroxyl group and a hydrogen)

hydrolysis

bonds are broken by the addition of a water group

ex: digestion- food in form of polymers is attacked by enzymes

True or False: The monomers made from hydrolysis can be used again in a dehydration reaction.

True

Why are polymers so diverse throughout species?

There are tons of different monomers that could make them up.

What are the four kinds of macromolecules?

carbohydrates, lipids, proteins, nucleic acids

carbohydrates

scourge of energy and provide structural support

- polymer

proteins

wide range of functions that includes catalyzing reactions and transporting substances

-polymer

nucleic acids

store genetic information and help with gene expression

- polymer

lipids

provide energy, make up cell membranes, and act as hormones

- not a polymer

What are the monomers of carbohydrates?

monosaccharides

What makes up monosaccharides?

a carbonyl group and multiple hydroxyl groups

-location of carbonyl group dictates when the monosaccharide is aldose or ketose

aldose monosaccharide

carbonyl group at end

ketose monosaccharides

carbonyl group in the middle

disaccharides

Carbohydrates that are made up of two monosaccharides and joined by a covalent bond

What are two reasons for carbohydrate diversity?

- the way simple sugars have their parts arranged around asymmetric carbons

- size of the carbon skeleton

What can monosaccharides serve as?

major fuels for cellular work

- their carbon skeleton acts as raw material for synthesis of other small organic molecules

glycosidic linkage

a covalent bond formed by two monosaccharides due to a dehydration reaction

polysaccharides

polymers w few hundred to thousands of monosaccharides joined by glycosidic linkages

what determines a polysaccharides function?

it's monosaccharides and it's glycosidic linkage positions

storage polysaccharides

plants and animals use these to store sugar for later

how do plants store sugars in storage polysaccharides?

they store starch as starch granules within plastids

ex of plastic: chloroplast

-synthesizing starch lets the plant stockpile glucose

How is sugar withdrawn from storage polysaccharides?

sugar can be withdrawn through hydrolysis

What are two starches?

- amylose (unbranded)

- amylopectin (more complex and branched)

What sugar do animals store?

Glycogen (a polymer of glucose)

-similar to amylopectin, but more branched

Where do vertebrates store glycogen?

Mainly in liver and muscle cells

What does breaking down glycogen do?

Releases glucose

What are the benefits of the extensive branches on glycogen?

there are more free ends for breakdowns

structural polysaccharides

used to build strong materials

What kind of structural polysaccharide is a major component in cell walls?

cellulose

what is cellulose

polymer of glucose with 1-4 glycosidic linkages

What happens when glucose forms a ring like shape?

the hydroxyl group is either above (beta b) or below (alpha a) the ring plane

-starch has a, cellulose has b

cellulose

-straight and never branched

-the glucose monomers can hydrogen bond with hydroxyl groups

-parallel cellulose in plant cell walls form microfibers (strong building material)

-helps food pass through digestive tract

(ex: cows eat protists or prokaryotes (microbes) that can hydrolyze the cellulose in hay + grass)

What are enzymes that dissolve starch NOT able to do?

dissolve the b (beta) form

What structural polysaccharide do arthropods use to build their exoskeletons?

chitin

chitin

-chitin embedded proteins are soft, but become hard when those proteins are chemically linked (insects), or encrusted w calcium carbonate (crabs)

- can be found in fungi, and they use it for their cell walls

-has b linkages, but their glucose have a nitrogen containing attachment

lipids

- usually don't include true polymers, and not big enough to macromolecules

-hydrophobic

fats

-not polymers, but large molecules assembled from small molecules by dehydration reactions

-consists of a glycerol molecules joined to 3 fatty acids

What makes up glycerol?

its an alcohol w/ 3 carbons that each have a hydroxyl group

what makes up a fatty acid?

long carbon skeleton and the carbon at the end is a part of a carboxyl group

Why do fats separate from water

because water molecules form hydrogen bonds with each other and exclude the fats

How do fatty acids join to glycerol

a dehydration reaction, specifically an ester linkage

ester linkage

a bond between a hydroxyl and carboxyl group

saturated fatty acid

if there are no double bonds between carbon atoms composing a chain, then as many hydrogen atoms as possible are bonded to the carbon skeleton

unsaturated fatty acid

A fatty acid that has one or more double bonds between carbons in the hydrocarbon tail. Such bonding reduces the number of hydrogen atoms attached to the carbon skeleton.

True or false: Most double bonds in fatty acids are cis which means they have kinks in the hydrocarbon chain

True

True or False: Trans fats can contribute to coronary heart disease.

true

What is a major function of fats?

energy storage (they actually store more energy that polysaccharides)

energy storage- plants

can function w/ energy in starch form since they don't move

energy storage - animals

-use fats as energy storage while they move in adipose swells that swell and shrink as fats go in and out

-adipose tissue also cushions vital organs

phospholipids

-major components of cell membrane

-similar to a fat molecule, but they only have two fatty acids attached to glycerol

- the hydroxyl group of glycerol joins to a phosphate group w/ a negative charge in the cell (usually have an additional small charged or polar molecule attached)

-tails are fatty acids (hydrophobic

-heads are hydrophilic

steroids

-contain a carbon skeleton w/ four fused rings

-distinguished by particular;ar chemical groups attached to rings

-cholesterol is a type of steroid that helps in cell membranes, and synthesizing other steroids (synthesized in liver and obtained from a person's diet)

proteins

-make up more than 50% of the dry mass in the cell

-some speed up chemical reactions, storage, transport, cellular communication, movement, or structural support

-constructed by 20 amino acids, linked in unbranched polymers

-made of one or more polypeptides

True or false: Most enzymes are proteins, a type of enzyme is a catalyst that speeds up a reaction without being used up.

true

amino acids

organic molecules with carboxyl and amino groups

What part of the amino acid determines its characteristics?

the r group (side chain)

- non polar side chain = hydrophobic

-polar side chain = hydrophilic

-acidic or basic = hydrophilic

Polypeptides (Amino Acid Polymers)

-carboxyl groups from two adjacent amino acids join together via a dehydration reaction and form a peptide bond

-repeating that forms a polypeptide

-each have a unique linear sequence of amino acids

-one side of it has a free amino group (N-terminus) and the other side has a free carboxyl group (C-terminus)

True or False: Amino acid sequences determine the protein's three-dimensional shape

True

-fibrous proteins: long fiber shape

-globular proteins: roughly spherical

what are the four levels of protein structure?

primary, secondary, tertiary, quaternary

primary structure

-a protein's sequence of amino acids

-determined by inherited genetic info

-dictates secondary and tertiary structure because of the backbones chemical nature and the side chain's of the amino acids along the polypeptide chain

secondary structure

- a polypeptide chain's coiled or folded segments

-due to weak hydrogen bonds between repeating constituents of the polypeptide backbone

-even though they're weak, the hydrogen bonds are repeated for a long time

a helix

-coiled

-is from hydrogen bonding between every fourth amino acid

B pleated sheet

-two or more segments of a polypeptide chain (B strands) are connected by hydrogen bonds on some parts of it

tertiary structure

-overall shape of a polypeptide chain resulted from interactions between the side chains of many amino acids

hydrophobic interactions

a type of weak chemical interaction caused when molecules that do not mix with water coalesce to exclude water (amino acids w/ hydrophobic side chains end up in clusters at the core of the protein)

disulfide bridges

Strong covalent bonds formed when the sulfur of one cysteine monomer bonds to the sulfur of another cysteine monomer

quaternary structure

-two or more polypeptide chains used to make one macromolecule

sickle cell disease

a change on the sixth amino acid in primary structure changes protein's secondary and tertiary structure, which leads to a straight chain like quaternary structure

denaturation

-a protein leaves its range of tolerance in pH, salt concentration, or temperature, which can cause a protein to unravel (loses its original shape and becomes inactive)

-weak chemical bonds and interactions in the protein are destroyed

True or False: Misfolding of polypeptides can cause serious diseases (usually because of an accumulation of miss-folded polypeptides)

true

x-ray crystallography

uses the diffraction of an x-ray beam by the atoms of a crystallized molecule to determine a protein's 3D structure

DNA

-provides directions for its own replication, directs RNA synthesis, and through RNA< controls protein synthesis (gene expression)

-each chromosome contains one long DNA molecules

-when cells divide, DNA is copied and passed to the next gen of cells

-has information that's programs all of the cell's activities

True or False: DNA directs mRNA to interact w/ a cell's protein synthesizing machinery (ribosomes).

True

-in a eukaryotic cell, ribosomes are in cytoplasm and DNA in the nucleus

- mRNA carries genetic instructions to cytoplasm

-in prokaryotic cells, (no nuclei), mRNA is still used in the same way

nucleic acids

-have monomers of nucleotides

-

nucleotide

-composed of a five-carbon sugar (pentose), a nitrogenous base, and one to three phosphate groups

True or False: The beginner monomer used to build a polynucleotide has 3 phosphate groups, but 2 are lost in polymerization

true

What is the portion of nucleotide w/o any phosphate group called?

nucleoside

Pyrimidine

-has one six-membered ring of carbon and nitrogen atoms

-cytosine and thymine

Purine

six-membered ring fused to a five-membered ring (adenine, guanine)-adenine and guanine

What is the sugar in DNA? In RNA?

deoxyribose and ribose

True or false: A nucleotide is also called a nucleoside monophosphate if it has one phosphate group

true

What does the linkage of a nucleotide to a polynucleotide involve?

a condensation reaction

-specifically a phosphodiester linkage

phosphodiester linkage

a phosphate group covalently bonds to the sugars of two nucleotides (repeating sugar-phosphate backbone)

sugar phosphate backbone

-one end has a phosphate group attached to a 5' carbon (5' end)

-other end has a hydroxyl group attached to a 3' carbon (3' end)

DNA structure

-2 polynucleotide strands that for a double helix in opposite directions (antiparallel)

strands are complementary

RNA structure

-single strands, but can pair to itself or another RNA molecules

How is base pairing accomplished?

w/ hydrogen bonding

bioinformatics

The use of computers, software, and mathematical models to process and integrate biological information from large data sets.

genomics

study and comparison of genomes within a single species or among different species

protenomics

the study of sets of proteins and their properties

True or False: linear sequences of DNA molecules are passed from parents to offspring

True

-siblings have greater DNA similarity than unrelated individuals

True or False: Species that appear to be closely related based on their anatomy, have more similar DNA

True