unit 3 Flashcards
purpose of nucleic acid
storing and transmitting genetic information
how are nucleotides connected
condensation reaction
DNA bases
Adenine, Thymine, Guamine, Cytosine
RNA bases
Adenine, Uracil, Guamine, Cytosine
how are nitrogen bases connected
hydrogen bonds
anti parallel meaning
1 backbone of DNA must be uspside down
importance of complimentary base pairing
makes sure both cells get same DNA in cell division
DNA expression meaning
when DNA is used to build stuff for the cell
gene
part of DNA that’s used to build stuff
small amount
transcription and translation
Transcription
DNA information gets copied onto RNA
DNA pairs up with the RNA nucleotides
Translation
RNA gets taken to ribosome to be turned into protein
RNA and RNA pair up
DNA length
can be any lengths
multiply x4 by each added nucleotide
diameter is about 2 nanometers
small so a lot of DNA can be stored
how many nucleotides does a ribosome read at 1 time
3- called codon
what does the codon say
to add 1 amino acid
codon definition
triplet in RNA
how many different codons are there
64
exceptions to universal code
-mitochondria
-chloroplast
when does DNA replication happen
in the S phase of interphase
what does semi conservative replication mean
the new DNA strand is half old and half new
process of DNA replication
the DNA is unwound(flattened) and unzipped(hydrogen bonds broken) by the enzyme helicase. the sides are used as templates for new sides.
nucleotides pair up using complimentary base pairing.
where does DNA replication occur
nucleus
(small area means more concentration which means sped up chemical reactions)
what is DNA polymerase used for
makes sure that nucleotide is matching with DNA nucleotide
matches bases
builds covalent bonds for new DNA backbone
what is pcr
used to make many copies of single dna
what is needed for pcr
DNA strand
enzymes
new nucleotides
primer
temperature(breaks bonds instead of helicase)
polymerase
PCR steps
loading
heated up and denatured
cooled down
heated again to optimum temperature
TAQ polymerase makes new strand
DNA amplified many times in a couple hours
what is TAQ polymerase
comes from bacteria that lives in hot water meaning it has adaptation to withstand heat
what is gel electrophoresis
separates molecules by size and charge
gel electrophoresis steps
-amplified
-dna cut up
-put into wells in gel
- electric current separates molecules by size
what is DNA measured by
how many base pairs there are
-known ladder vs unknown sizes
how do we have different traits if we have same genes
we have different alleles that are repeated different amount of times
how does DNA profiling work
match known to unknown
identical means same person, similar means relative
DNA profiling examples
-forensic investigations
-databases
-paternity suit-need DNA of mother,father and child
transcription definition
when DNA code is copied onto RNA code
transcription steps
-dna is unzipped by RNA polymerase
-RNA polymerase matches nucleotides
-mRNA leaves nucleus and takes message to ribosome in cytoplasm for translation(only one side of DNA is transcriped to build RNA)
sense vs anti sense strand
sense: the unused strand
anti sense: the used strand
gene definition
part of DNA that’s transcribed then translated onto protein
what does DNA do during transcription
it unzips briefly then closes right away to protect DNA from radiation, chemicals, etc so genese stay the same
why isn’t helicase used in protein synthesis
so that the DNA zips back up and hydrogen bonds automatically reform
gene expression meaning
some genes are expressed and made into proteins and some do not.
this is the reason for differences between our cells, and also between ours and other peoples cells.
transcriptome definition
all of the transcripts/mRNA that get made in a persons cells.
-every person has unique
where does translation occur
on ribosomes
building block of protein
amino acids
translation steps
- mRNA attaches to ribosome
- ribosome reads 1 codon at a time(3 nucleotides)
- tRNA brings in amino acids based on codon its pairing with
- peptide bonds forms between amino acids
- anticodon leaves
- polypeptide forms
- polypeptide bends to make 3D shape and protein
what is rRNA
what ribosome is made of
what is an anticodon
bottom of tRNA that goes with codon
what is the start codon
AUG
- codes for methionine
what does degenerate code mean
same codons code for same amino acid
what is a mutation
any change in DNA
-change in amino acid>change in shape>change in DNA
base substitution
wrong added base
-usually no effect
beneficial mutation example
adaptations
what kind of mutation is sickle cell anemia
base substitution
cause of sickle cell anemia
codon is supposed to be GAG but GUG shows
glutamic acid to valine
themoglobin is abnormal and makes red blood cells change shape which means they’re not good at carrying oxygen and cant carry out cell respiration-causes tiredness and pain
GAG codes for what?
glutamic acid
GUG codes for what
valine
co dominant disease meaning
both alleles are dominant
why is sickle cell trait common
it gives resistance to malaria
gives advantage in Africa so it was passed down-natural selection
what makes DNA stable
base pairing, covalent bonds, and because it zips back up after being opened
types of mutations
same sense
non sense
missense
insertion
deletion
why might a mutation not cause a change
if its in place without genes
what is a same sense mutation
1 base is changed to another but codes for same amino acid(no change)
what is a non sense mutation
when a stop codon is added-dysfunctional protein- harmful
what is a missense mutation
changes codon which changes amino acid which changes protein-can be beneficial(adaptations), harmful(disease), or neutral(hair color)
what is an allele
different form of same gene-started as mutation
single nucleotide polymorphism
place in DNA sequence where 1 allele is different than others
what is a frame shift mutation
insertion or deletion
-harmful because all amino acids are changed
-whole codons doesn’t necessarily change protein because it doesn’t affect base pairing
what is the BRCA 1 gene
-gene used for breast cancer predictions
-20000 variants/alleles
what is a mutagen
anything in environment that increases chance for mutation
mutagen examples
radiation
chemicals
what are somatic cells
normal cells
mutations usually aren’t affective unlecc cancerous
oncogenes definition
make protein that regulate cell cycle
what kind of cells contain mutations that can be passed down
germ cells-egg or sperm
what is a genome
all DNA in organism- how much and what order
similarities in genomes between species
same species have very similar genome, especially in same population
differenct species having similar genome size comes from evolution
differences in genomes between species in different populations
different populations develop different traits which changes into different species over time by natural selection
they have different genes and different sized genomes but always same genetic code
what is genome sequencing
the exact order of code
(A,T, G, and C’s)
what were the 1st genomes sequenced
simple like viruses and bacteria
human genome project
attempt to sequence 3 bill base pairs
we invented new tech
now we can sequence human genome in few weeks
what is the purpose of adding more organisms to be sequenced
to add to “knowledge database” and to compare to human genes to study
benefit to human genome sequencing
identifying possible diseases
how do chromosomes compare across different species
genes are located in different chromosomes between different species
-different # and type
what are chromosomes like in prokaryotes
1circular
what are chromosomes like in eukaryotes
many linear
they match up
even number
what are diploid cells
2 sets of chromosomes
-most human cells
what are haploid cells
1 set of chromosomes
-reproductive cells
role of diploid and haploid cells in reproduction
haploid cells fertilize each other to create diploid cells in offspring
Offspring will have half chromosomes from mom, and half from dad.
number of chromosomes in humans
46
-23 in each set
what does staining do for seeing chromosomes
increases contrast of chromosomes so that they can be seen better
-stains attach to proteins really well
where does a karyogram come from
metaphase in mitosis
what is a karyogram
picture of chromosome
female chromosomes
xx
male chromosomes
xy
what organisms does meiosis happen in
sexually reproducing eukaryotes
process of meiosis simple
meiosis splits homologous pairs in diploid cells into haploid cells
meiosis produces gametes
why must sexual organisms produce haploid cells
sperm and egg fuse so that haploid cells can create diploid cells and produce zygote
what is a gamete
sexually reproductive cells-egg or sperm
what is a zygote
fertilized egg after gametes meet
prophase I
-nucleus dissolves
-chromosomes condense
-mtoc forms
-2 homologous chromosomespair into bivalents by synapsis to make sure they’re evenly split
-crossing over happens- exchange of dna
where does crossing over happen
the chiasmata
what is genetic variation
lots of different combinations of genes due to crossing over
metaphase I
homologous pairs align in middle by mtoc
anaphase I
bivalents pulled apart by mtoc
telophase I
2 new nuclei form
mtoc dissolves
chromosomes decondense
cytokinesis I
split into 2 non indentical haploid cells
prophase II
nucleus dissolves
chromosomes condense
mtoc forms
happening in 2 cells at one time
metaphase II
chromosomes moved to middle by mtoc
anaphase II
chromatids pulled apart by mtoc
telophase II
chromosomes decondense
4 nuclei form
mtoc dissolves
cytokinesis II
4 non identical haploid cells
sources of genetic variation
- crossing over
- random orientation- in metaphase, randomly split in anaphase
- random fusion of gametes-any egg can fertilize any sperm
what is non disjunction
chromosomes don’t separate like theyre supposed to causing resulting cell to have extra or not enough
what is down syndrome
chromosome 21 sticks to itself causing there to be an extra
symptoms : learning disability, flattened face and hands, health problems. benefits like happiness and friendliness
inheritance definition
how traits get passed from parents to offspring
crossing traits
breeding to produce offspring
P1 generate make F1 gen which makes F2
-mendel did this manually with pea plants to make sure they didn’t self pollinate
what is a genotype
combination of alleles
what is a phenotype
what it looks like
-comes from genotype or environment
what is phenotype plasticity
environment changes DNA which then changes phenotype
phenotype plasticity example
arctic fox’s fur changing color in different seasons
what makes alleles different
the base pairs
what is the place where alleles are different
single nucleotide polymorphism
why are most diseases in humans recessive
if it was dominant we would die before passing it on
what is pku
on chromosome 12
both chromosomes have to have it
protein made is called phenylalanine hydroxylase which is converted to tyrosine
causes tyrosine to go down and phenylalanine to go up
causes brain delays and disabilities in babies
how are pregnant mothers screened for pku
checking amino acids and DNA sequencing
pku treatment
diet of intaking more tyrosine and eating less phenylalanine
what does it mean to have multiple allele trait
more than 2 options
genotype has more possibilities for alleles
-still only 2 alleles from parents
-creates blend of traits
gene pool
all possible alleles within population
-includes likelihood
gene pool examples
S gene in apples
-32 different alleles
-prevent self fertilization
-evolved over time to increase genetic variation
Blood type
-A, B, AB, O
-alleles code for glycoproteins which are often antigens
blood type alleles in punnett square
A- I^A
B-I^B
O- i
codominant trait in phenotype
both traits show up at same time
incomplete dominance
when 2 traits mix together
incomplete dominance example
marvel of Peru flowers
-white +red flower=pink flowers
what is an autosome
the 22 pairs of chromosomes that aren’t sex chromosomes
differences in traits between x and y chromosomes
x chromosomes are larger and carry more genes
carry different genes than y
y chromosome has tdf gene which makes embryo male
what are the genes on sex chromosomes called
sex linked
how did Thomas hunt morgan find that white eyes in fruit flies are sex linked
they were present mainly in males
why is color blindness more common in males
males only need 1 recessive allele for it. there is nothing covering the allele.
what is hemophilia
there’s a gene on x chromosomes that makes blood clot and with hemophilia the protein is made wrong
what is a pedigree
helps track trait in families/sees if you have allele in DNA
what things lead to genetic diversity
multiple alleles, codominance, incomplete dominance, and sex linked chromosomes
how are many of our traits affected by more than just 1 gene
multiple different proteins make 1 trait
what is polygenic inheritance
genes make many different proteins which work together to make trait
what is discrete variation
different options are very different
example of discrete variation
blood type
what is continuous variation
blend of traits so you can’t always see difference
-normal distribution: most at average
continuous variation example
height
skin color
-environment affects these
mitosis vs meiosis
Both: form of cell division, interphase happens first
Meiosis: -reduction division
-produces sexually reproducing cells
-produces 4 genetically different haploid cells
Mitosis: -produces 2 genetically identical diploid cells
-keeps number of chromosomes the same
-for growth and cell replacement
why are alleles different
different base sequence
