Bio exam 1

aminoacyl-tRNA synthetase

enzyme that covalently links amino acid to the correct tRNA

How many types of aminoacyl-tRNA synthetase are there

20

codons

made up of three nucleotides that represent an amino acid

anticodon

complementary of mRNA codon

start codon

AUG

the liver and the human neuron have the same genome but they are different why?

gene expression

the most common control point for eukaryotic gene expression

transcriptional control

genome

the genetic material unique to each species

alleles

different versions of genes

single nucleotide polymorphism

single nucleotide differences due to a mutation

phenotypes are mainly caused by

SNP- single nucleotide differences

synonymous mutation

silent. alters the codon but does not change the resulting amino acid

non synonymous mutation

creates a new polypeptide

germ-line cell mutations

occur in reproductive cells and can be passed down

somatic cell mutations

occur in body cells of individual, cannot be passed down

why does an egg only urge 20-30 rounds of DNA replication?

females are born with all their eggs. this leaves less room for making copying errors.

who does sperm go through 200 rounds of DNA replication?

sperm is continuously produced, leaving more room for error. DNA replication must be more to filter out errors

describe mutation in regulatory DNA

doesn’t change amino acid but changes level of expression.

regulatory dna

controls when, where, how DNA is expressed.

example of regulatory DNA change

lactase was only expressed in infants. a mutation led it be expressed in adults too. (not all; lactose intolerance)

what is an example of gene duplication and divergence

meiosis and unequal crossing over

globin genes such as hemoglobin and myoglobin evolved from

gene duplication

purines have how many rings

2 rings

pyrimidines have how many rings

one ring

where is the phosphate group attached to?

5’ carbon of the sugar

how are the strands of the DNA helix characterized

anti-parallel and complementary

what gives DNA molecules negative charge?

phosphate group

The information encoded in DNA resides in

DNA Base sequence

what recognize(s) the stop codons UAG, UAA, and UGA.

Release factors

describe heterochromatin

compact and dense. packed in nucleus during interphase

Telomere

heterochromatic sequences at the tips of DNA molecule forming a cap at each end

centromere

indentation on the site of a chromosome where mitotic spindles attach

what two monosaccharides form lactose

glucose and galactose

what do rRNAs do

recognize and bind molecules, catalyzes reaction that covalently links amino acids, support structure

what is the role of transcription factors

help RNA polymerase recognize promoters

The nucelous is made from

clusters of rRNA

ribosomes are made up of

rRNA and proteins

RNA polymerase III transcribes the (SMALLEST/LARGEST) RNA sequences

SMALLEST

RNA Polymerase transcription factors are located on ___’ side of each transcription unit

5’

what is the polyadenylation sequence

AAUAAA

what is the relationship between the poly A tail and the polyadenylation sequence.

the poly A tail begins 20 bases down from polyadenylation sequence

what is the minimum amount of tRNA that a mammalian cell could have

20

why can tRNA recognize many codons

wobble hypothesis: first and second codon are fixed. third codon has variance

Polar molecules contain

O-N-S-P

Nonpolar molecules contain

C,H

The cytoplasm is made up of

organelles and cytosol

The nucleus is

not apart of the cytoplasm

Tell me the story of Henrietta lacks

She had HELA cells. HeLA cells are immortal cells that were derived from cervical cancer. They are immortal because telomerase rebuilds the ends of the chromosome.

describe covalent bonds

strong, broken using enzymes, keep organic molecules together, energy is stored in bonds

BARF

Break, absorb, release, form

Why do we say that energy is stored in bonds

products have less usable energy than reactants

polar bond

unequal sharing

non-polar bond

equal sharing

describe noncovalent bonds

important for correctly folding macromolecules, important for holding molecules together, relatively weak, not sharing electrons; attractive force

electrostatic interaction

attraction between opposite charges

name the 4 types of non-covalent bonds that bring molecules together

ionic, hydrogen, van der Waals, and hydrophobic force

hydrogen bond

dipole-dipole between a hydrogen atom covalently bound to a highly electronegative atom and another nearby electronegative atom

what type of charges form hydrogen bonds

partial charges

how do hydrogen bonds affect stability

they form arrays or crystals; stabilize 3 dimensional proteins

4 types of macromolecules

carbs (monosaccaride), lipids, nucleic acid (nucleotides), proteins (amino acids)

types of polymers

carbs (monosaccaride), nucleic acid (nucleotides), proteins (amino acids)

_____ are a macromolecule but not a polymer

lipids

hydrolysis

breaks bond using water molecule; releases energy

condensation

builds bonds; water as a byproduct

Describe how covalent and non covalent bonds work to form a macromolecule

covalent bond binds subunits, non covalent bonds stabilize macromolecule and folds it into correct shape

what are the 3 forms of carbs

monosaccharides, oligosaccharides, and polysaccharides

functions of carb

stores cell energy in covalent bonds

_____ Is the key molecule in the metabolism plants and animals

glucose

identify this

monosaccaride

identify this and the bond in between

disaccharide; bond is covalent glycosidic

sucrose is made of

glucose and fructose

lactose is made of

glucose and galactose

how do u distinguish between glucose and fructose

fructose - five sides. glucose six sides

how to differentiate between glucose and galactose

on galactose 4 prime, OH points up

what are the 3 forms of lipids

fats, steroids, and phospholipids

functions of lipids

energy storage 2x more than carb, membrane structure, specific biological functions

triacyglycerol

3 fatty acids + 1 glycerol

saturated fatty acid

no double bonds

unsaturated fatty acids

double bonds in tail (kinked shape)

amphipathic

polar and nonpolar

the more double bonds the more _____ at room temp

liquid e.g oil

describe phospholipids

glycerol + 2 fatty acids + phosphate group bond to polar group

amphiatic and makes up backbone of cells

______ head, _____ tails (2_

hydrophilic head, hydrophobic tails

name one type of sterol

cholesterol (membrane component and hormone precursor)

describe sterols

4 ring structure

Nucleotides link together through ______ bonds

3’, 5’ phosphodiester

describe structure of nucleotides

phosphate + sugar + nitrogenous base

what is the difference between deoxyribose and ribose

deoxyribose lacks an oxygen on 2’ carbon

DNA functions

template for daughter genome

template for and RNA production

what bond connects two dna molecules in a double helix

hydrogen bonds

RNA is ____ strand with ____ regions

single;double

primary structure

linear sequence of amino acid making up polypeptide chain.

amino acids are held together by

peptide bonds

average human protein contains ____ amino acids

about 400

significance of amino acid sequence

determined by gene

determines shape and function

changes in sequence are caused by mutations in DNA

once part of a polypeptide, an individual amino acid is call a

residue

____ give amino acids their unique properties

side chains (r groups)

secondary structure

conformation of a PORTION of polypeptide chain

What stabilizes the secondary structure of an 𝛼-helix, and what is its specific bonding pattern?

Hydrogen bonds

The amino acids held together by peptide bonds.

C=O bonds to N-H

N-H group 4 steps ahead.

Side Chains: Stick out, away from the spiral.

a-helices ___ cross lipid bilayer

can