bio exam

deoxyribonucleic acid

full name for DNA

DNA

instructions to build proteins, "blue print"

genes

portions of DNA that codes for a protein

proteins

causes traits to appear in the phenotype

estrogen, insulin, melanin, enzymes

examples for proteins

chain of nucleotides

what is DNA made of?

1 base, 1 sugar, 1 phosphate

what makes a nucleotide?

ademine (a), guanine (g), cytosine (c), thymine (t)

list all of the bases

ademine (a), guanine (g)

list the purine bases

cytosine (c), thymine (t)

list the pyrimidine bases

bases need to be in a specific order (A+T , C+G)

base pairing rule (and list them)

2

how many hydrogen bonds do A+T have?

3

how many hydrogen bonds do C+G have?

to bind bases together and allow DNA to separate

why does DNA have weak hydrogen bonds?

mutation

what occurs when the wrong bases bind together (A+C, A+G, T+C, T+G)

double helix

what shape is DNA?

rosalind franklin

used X-ray crystallography and discovered that DNA is a double helix --\> got photo of cross in DNA

watson + crick

wins Nobel Prize for discovery of DNA in 1962

watson + crick

see photo on franklin's desk --\> sketches photo + puts it in the paper

DNA replication

DNA unzips into two parts and splits with the cell --\> copy made of one side (mRNA) and transported to make a protein

results in 1 new stand + 1 old strand of DNA

semi-conservative

transcription

copy of DNA is made using messenger RNA (mRNA); in nucleus; opens to make the copy, then closes when mRNA leaves

protein synthesis

chain of amino acids joined by peptide bonds

20

how many amino acids are there?

ribonucleic acid

full name for RNA?

RNA: 1 strand, ribose sugar, no thymine, but uracil (u) -- DNA: 2 strands, deoxyribose sugar, has thymine

difference of RNA and DNA

code for amino acids

codons

carries 1 amino acid and anti codons into cytoplasm

transfer RNA

opposite of codons on mRNA

anti codons

initiation, elongation, termination

steps of translation

START codon (AUG)

initiation

adding amino acids to the chain

elongation

involves single gene

point mutation

STOP codon (UAA, UAG, UGA)

termination

mostly recessive, causes variation, sudden + accidental change, most are bad

mutations

missense mutation

a base substitution that causes an amino acid substitution

missense mutation ex.

sickle cell

nonsense mutation

instead of an amino acid the codon codes for STOP (shortens the protein code)

nonsense mutation ex.

cystic fibrosis

frameshift mutation

addition or deletion of a base

frameshift mutation ex.

tay sachs

cancer

unrestrained cell growth and division

malignant and benign

types of tumors

number of mutational events, non-functioning immune system

for malignant tumors to occur:

mutagens, inheritance, viruses

causes of illnesses/cancer

UV, radiation, chemicals

Mutagens that can cause cancer

predisposition

inheritance of cancer --\> likelihood is greater

breakage and restitution

what causes abnormality in the chromosome structue?

breast, colon, prostate

predisposition cancers

viruses

submicroscopic parasites of cells (host specific)

DNA virus ex.

herpes

retrovirus (reverse transcription)

RNA virus

RNA virus ex.

HIV

protooncogene

gene for normal cell division

pncogene

gene for unrestrained cell division (cancer)

sex chromosomes

what chromosomes are the 23rd pair called?

23

what number pair are the sex chromosomes?

sex linked traits

traits linked through the sex chromosomes

affected or normal

carrier mothers have the possibilities of having affected/carrier/normal sons?

do carrier mothers have a chance of having a carrier son?

No --\> has one affected and one normal son

hemophilia

condition where blood doesn't clot

pedigree

what is the map that traces inheritance called?

Recessive

On a blank pedigree, if two normal parents have an affected child, is the disease dominant or recessive?

Dominant

On a blank pedigree, if two affected parents have a normal child, is the disease dominant or recessive?

monogenic traits

traits that are controlled by a single gene

polygenic traits

traits controlled by multiple genes and affected by the environment

blood type

1 example of monogenic trait

stature, skin color

2 examples of polygenic trait

melanin

what determines your skin/hair/eye color

Why is melanin important?

blocks UV rays

What is one bad thing about UV rays?

can cause skin cancer

What is one good thing about UV rays?

give the body make vitamin D

Why is vitamin D important?

(works alongside calcium) Helps build/repair bones

Why do tropical places have more melanin in their skin?

To help avoid skin cancer

Why do northern places have less melanin in their skin?

To help with vitamin D production

What is a vitamin D deficiancy?

Rickets

what cause variation in the population?

random assortment, crossing over, mutation

mutation

sudden, accidental change in the structure or amount of genetic material

point mutation and chromosomal mutation

types of mutations

point mutation

mutation in a single gene

chromosomal mutation

mutation that involves all or part of a chromosome

mutagens

environmental factors that cause mutations

UV, radiation, x-rays, chemicals, tobacco, alcohol

examples of mutagens

what causes chromosomal mutations?

nondisjunction

nondisjunction

failure of the chromosomes to separate during meiosis

what is the result of nondisjunction?

2 gametes w/ one too little and 2 gametes w/ one too many chromosomes

monosomy

lacking a chromosome

trisomy

having an extra chromosome

sex chromosome nondisjunction examples

XYY male (supermale - trisomy 23), XXY (klinefelter syndrome - trisomy 23), XO (turner syndrome - monosomy 23)

autosomal nondisjunction example

down syndrome (trisomy 21)

breakage

a piece of the chromosome breaks off

restitution

the chromosome puts itself back together after a piece breaking off

duplication and deletion, inversion, and translocation

abnormalities caused by breakage and restitution

which of the abnormalities in chromosome structure happen in non-homologous pairs?

translocation

example of duplication and deletion

cri-de-chat syndrome

What are the steps of the scientific method?

problem/question, hypothesize, test, conclusion

problem

something you have a question about

something visible while making your problem

observation

something you have prior knowledge with while making your problem

interference

hypothesis

educated guess