Foundations in Biology Exam One

what do carbohydrates contain

carbon

• contain carbonyl group

hydroxyl groups

carb functions

• serve as a source for NRG

• a mechanism to store NRG in cells

• provide structure for plants

fungi

three states of carbs

- monosaccharides

- disaccharides

- polysaccharides

monosaccharides

one monomer of carbs

- polar (hydroxyl groups)

- hydrophilic

- depending on the number of Carbons present

they may have different names

- glucose

fructose

disaccharides

two monomers of carbs get linked together

- formed through dehydration synthesis or a condensation reaction

- disaccharides are made up of two monosaccharides joined together by a condensation reaction

- (i.e. glucose and ribose)

what bond links individual monomers in carbs (what type of bond joins two monosaccharides to form a disaccharide)

glycosidic bond

polysaccharides

- polysaccharides are polymers formed by combining many monosaccharides molecules (more than two) by condensation reaction

- in other words

a polysaccharide is a long chain of monosaccharides joined together with glycosidic bonds

- molecules with 3-10 sugar units are known as oligosaccharides while molecules containing 11 or more monosaccharides are true polysaccharides

- cellulose

- starch

- glycogen

cellulose

the major component cell walls in plants

starch

is the main NRG storage materials in plants

glycogen

the main NRG storage material in animals

common polysaccharides

• chitin

• cellulose

• peptidoglycan

- glycogen

chitin

a nitrogen containing polysaccharide that makes up the cell wall in fungi and exoskeleton of arthropods (insects and crustaceans)

cellulose

component in cell wall of plants that provides a rigid structural function for the cell wall

peptidoglycan

polysaccharide that makes up the cell wall in eubacteria ( not archeabacteria or all prokaryotes)

starch and glycogen

polysaccharides utilized in plants and animals cells as a NRG storage molecule

describe peptidoglycan structure

- in the figure: we see long chains of monosaccharides linked together to form the polysaccharides

- in green there are oligopeptides

- peptide refers to proteins

so the green structures represents short protein chains attached to the polysaccharide chains

The individual peptide chains link together the individual polysaccharide chains

- when two protein chains bond together in this way we call is crosslinking

- this allows for the very strong rigid cell wall we see in eubacteria

what is the stoichiometric formula for carbohydrates

(CH2O)n

what is a monnosaccharide

they are simple sugars

how does penicillin work

antibiotic that targets peptidoglycan in bacterial cell walls

- there is an enzyme in bacterial cell walls called transpeptidase that is responsible for joining the protein chains together to form cross-linking

- penicillin binds to the transpeptidase enzyme and prevents it from functioning so the cells can no longer cross-link peptidoglycan chains together

weakening them

The stoichiometric formula (CH2O)n

where n is the number of carbons in the molecule represents carbohydrates. In other words

glucose

galactose

monomers that make up nucleic acids

nucleotides

how do we commonly know nucleic acid

as DNA and RNA

- the individual monomers that make up the chains of DNA and RNA are called nucleotides

describe the structure of nucleotides

5-carbon sugar linked to a nitrogenous base and a phosphate group

two different types of sugars we see in different nucleic acids

- ribose

- deoxyribose

ribose

- five-carbon sugar present in RNA

- contains an OH group on its 2' carbon

deoxyribose

- five-carbon sugar that is a component of DNA nucleotides

- lacks OH group on 2' carbon

• has H on 2' instead

• both sugars to have OH group on 3'

however

how do we label carbon in nucleotides

as primes

• i.e.

1 prime

5 nitrogenous bases found in nucleic acids

cytosine

uracil

only in RNA

thymine

only in DNA

how are these 5 nitrogenous bases categorized into broad categories

split into pryimidines and purines

pryimidines

pyrimidines contain a 6 member ring

• cytosine

uracil (only in RNA)

pruines

consist of a 5 member ring fused to a 6 member ring

• guanine and adenine

how do individual monomers link to form our nucleic acid chains

condensation reaction/dehydration sythesis reaction occurs forming a phosphodiester bond

- covalent bonds

- the 3' OH group joins with the phosphate group located on the 5' carbon

linking the two nucleotides together

what is the backbone of nucleic acids

sugar-phosphate backbone

- we are linking together the sugar of one nucleic acid to the phosphate of the next

orientation of nucleic acids

very important

- the 5' carbon binds to a phosphate group and the 3' carbon is bound to a OH group

- this gives nucleic acids polarity

- there are different chemical groups on the 5' end and on the 3' end

bonds of double stranded nucleic acid

two chains of nucleic acid binds to one another though hydrogen bonding between the nitrogenous bases

- complementary base pairs hold DNA strands together in the double helix

how do Hydrogen bonds form between nitrogenous bases

any two bases can form hydrogen bonds with one another

base pairing rules in DNA

guanine with cytosine: will from 3 H bonds

adenine with thymine (uracil): will form 2 H bonds

why is orientation important

in ds DNA

5' end of one strand will pair with 3' end of another

primary structure in nucleic acids

- DNA: sequence of nucleotides (sequence of individual bases)

- RNA: sequence of ribonucleotides (AUGC)

secondary structure nucleic acids

- DNA: forms through the H bonding between nitrogenous bases

- RNA: hairpins formed when single strand folds back on itself to form a double-helix stem and unpaired loop (very rarely does it form with two strands)

tertiary structure of nucleic acids

- DNA: double helix forms compact structures by twisting into super coils or wrapping around proteins

- in eukaroytic cells and archeabacteria the DNA will wrap up with histone proteins

forming chromatins

- RNA: secondary structures fold to form a wide variety of distinctive three-dimensional shapes (tRNA)

the secondary structure of DNA is

the double stranded helix

what are the two main types of nucleic acids

deoxyribosenucleic acid (DNA) and ribonucleic acid (RNA)

what is the genome of a cell

the cell's entire genetic content is its genome