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Human Genetics

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When did cells first originate?
Prokaryotic was 3.7 Billion
What are the three domains?
Archaea, Eukarya, and Bacteria
What is binomial nomenclature?
Formal naming system for a species
Name the components of a Somatic Cell?
Cell membrane, nucleus, cytoplasm, organelles, mitochondria, and ribosomes
What three people discovered DNA?
Watson, Crick, and Rosalind
Covert this DNA template strand to the complementary strand: 3' TAC CGG ATG CCA GAT CAA ATC 5'
5' ATG GCC TAC GGT CTA GTT TAG 3'
How many possible codons are there? How many amino acids?
64, 20
What is natural selection?
A process by which individual organisms with favorable traits are more likely to survive and reproduce than those with unfavorable traits
What are the components of a nucleotide?
a base, a sugar, and a phosphate group
What is RNAi?
Small portions of RNA that are complement to target mRNA
What is an SNP?
Base substitution or change
Indels
Insertion or deletion of a small number of nucleotides
What is CD4 and CCR5?
Receptors used to gain access into the host cell (HIV)
What happens if you have two copies of CCR5?
you are resistant to AIDS!
What is Epigenetics?
Inherited change in phenotype or genotype expression
What is Alternative Splicing?
Allows the cell to produce many versions of a protein from the same mRNA transcript
What are STR's
Short tandem repeats. Changes number of copies of a repeat of nucleotides
Trinucleotide repeats?
STR with a set of three.
What is a mutation?
Inherited change in genetic information.
How many genomes?
More than 1300 since 1993
Name three organisms that had their genomes sequenced?
Drosophila Melanogastor, mus musculus, and gallus gallus.
What is a genome?
The complete set of genetic material of an organism.
How many bases are in a human genome?
3.1 billion base pairs
How many chromosomes are in a human genome?
46 Diploid, 23 haploid
How many genes are in a human genome?
24,000
What is semi conservative replication?
How DNA replicates, each strand acts as a template for the double helix
What experiment determined semi conservative replication?
Medelson and Stahl's
What does helicase do?
unwinds the double helix
What do binding proteins do?
Stabilize seperate strands
What is primase?
Adds short primers to template strand
What is DNA polymerase?
Binds nucleotides to form new strands.
What is Exonuclease?
Removes RNA primer and inserts bases
What is ligase?
Joins okizaki fragments and seals backbone
What is CCL3L1?
Associated with susceptibility to AIDs
Name the four bases?
Adenine, guanine, cytosine, and thymine
Which bases are purines?
guanine and adenine
which are pyridimines?
cytosine and thymine
How is DNA complementary?
G is always with C and A is always with T
How is DNA anti parallel ?
directionality is in two different directions
What are Chargaff's rules?
Rule of proportion, A=T and G=C
Say A=10%, figure the rest.
T=10% G=40% and C=40%
How is nuclear DNA different from mtRNA?
nuclear is contained in nucleus, and mtDNA located in organelles and mitochondria
What are the 3 steps of translation?
initiation, elongation, and termination
What is non-disjunction?
Failure of chromosomes to seperate during meosis.
What is a CNV?
Copy number Variant, number of copies a gene can lead to differences in gene expression
What is proteomics?
Branch of genetics that studies set of proteins encoded by a genome
What are prions
They encourage misfoldings in normal proteins
What is gene expression?
Process by which inheritable info from a gene is made into a functional gene product
Components of blood?
RBC's, WBC's, platelets, and plasma
What are chromosome abnormalities?
Alternation in number of chromosomes
What is coding?
Makes a protein, compromises DNA, includes exons, regulatory genes turn of and on at appropriate time.
What in noncoding?
Function not fully understood, formally called junk, includes introns.
What happens in initiation?
mRNA binds to the ribosome, translation begins at codon
What happens during elongation?
tRNA brings an amino acid to the ribosome, tRNA brings another amino acid and attaches it to the first, continues adding amino acids to the peptide chain.
What happens during termination?
Translation ends when it reaches the stop codon
How does DNA condense during cell division?
It condenses with the histone, which gets shorter, to form a chromatin, which condenses to become a chromosome.
How is DNA duplicated through semiconservative replication?
It gives one strand to each new daughter strand. Unlike the other two forms of replication which either give both or at random.
What experiment was performed to determine semi conservative replication?
They used heavy and light nitrogen
Describe what happens to preMRNA before it becomes mature mRNA
premRNA goes through every DNA goes through. Now enters preadenalation (Asite) adding adenine. It goes through transcription only.
Describe gene expression in globin molecules over human development?
Babies have gamma, adults have alpha. Changes because of oxygen.
What are polymerase errors?
First cause of mutation, during replication of the genome to get ready for cell division the polymerase enzyme inserts the wrong base.
what are mutagens?
Another cause of mutation where substances that cause major damage to generic material
What is another cause of mutation?
Radiation, x-ray, UV radiation, gamma rays.
One type of technique to detect mutations?
Genome sequencing
What is PCR?
Polymerase chain reaction (DNA copy machine) chemically makes copies of the regions we are interested in
What types of abnormalities can nondisjunction lead to?
Trisomy 21
What affect does maternal age have on likelihood that a zygote will have a chromosomal abnormality?
80% under the age of 35
Why is the genetic code redundant and not ambiguous?
There are multiple base pairs that produce the same amino acid so it's not ambiguous because the sequence only codes for one protein not multiple.
How does alternative splicing add to diversity of biological function?
Because it allows the cells to produce many versions of a protein and yields different combinations of exons.
What is methylation?
Turns off chromosome before initiation of translation
What is Acetylation?
Remodels chromatin, histones letting go
Enzymes involved in replication?
Helicase, binding proteins, exonuclease, primase, polymerase, and ligase
What are introns?
The segment of DNA or RNA that does not code for proteins and interrupts the sequence of genes.
What are exons?
Segment of DNA/RNA molecule containing info for coding a protein sequence.
What is a gene?
Any DNA sequence that is transcribed into an RNA molecule
What is a chromosome?
A highly wound continuous molecule of DNA and the proteins wrapped around it
What is the primary level of protein?
Sequence of amino acids
What is the secondary level of proteins?
Shapes formed with regions of proteins
What is the tertiary level?
Shape of entire folded protein
What is the Quaternary level?
Structures formed by interactions of several proteins.
What is a protein?
Biological macromolecules, strings of amino acids, and participate in every cell process.
What is DNA replication?
Cells multiply by dividing, copied by semi conservative replication, the original strand is a template for the new strand, and always made in the 5'-3' direction
What is RNA transcription?
DNA is copied to mRNA, modified to contain only certain important information, mRNA passes through membrane and into the cytoplasm
Explain RNA
Ribonucleic acid, contains uracil not thymine, and single stranded.
What is translation?
premRNA becoming mature mRNA mature mRNA is used to direct the synthesis of a polypeptide.
DNA vs. RNA
DNA is double stranded, RNA is single, the type of sugar, and bases used.
What is a regulatory gene?
Determines whether or not genes will be expressed
What is a structural gene?
Determines the amino acid sequence of a protein.
Describe translation
mRNA binds to the ribosome, tRNA brings the amino acid, tRNA brings another and attches it to the first, this continues until it reaches a stop codon and releases a new protein
What is meiosis?
Cell division that halves the number of chromosomes to form haploid gametes.
What is mitosis?
Division of nonsex cells.
What process is involved with growth and healing?
Mitosis
What is crossing over/recombination?
It generates genetic diversity by recombining genes and gametes.
Where is a gene mutation?
in DNA
What is a splice site mutation?
Removal of an intron or exon
Point mutation?
change in a single base
Is the daughter cell in mitosis different that the parent cell?
No, its identical
Is the daughter cell in meiosis different than the parent?
yes
What is the role of meiosis?
To produce gametes
How many daughter cells does meiosis have?
4 haploid
How many daughter cells does mitosis have?
2 diploid
What are the phases of the cell cycle?
Prophase, metaphase, anaphase, telophase
During which phase is DNA synthesized?
interphase
During which phase do cells divide?
M phase
Silent (synonymous) mutations
SNP in a codon that does not change the amino acid
Familial hypocholesterolemia
bad cholesterol levels, dysfunctional LDLR gene, can be result of missense, nonsense, or splice site mutation
Nonsense mutation
SNP that changes a sense codon to a premature stop (Hemophelia B)
Missense mutation
SNP that alters one amino acid, B globin mutation. Causes sickle cell anemia
What happens if there is a mutation in the promoter of a gene?
Can lead to alzheimers
What is a karyotype?
A human made arrangement of all the chromosomes of a cell
What are autosomes?
Non sex chromosomes
How many sex chromosomes does a male have? Females?
1x and 1 y females have 2 xs
What is trisomy 13?
Patau syndrome, eyes are very small, partial or complete deafness, rare to live beyond a few weeks.
Aneuploidy?
Alteration in chromosome number, Down syndrome, turner's, klinefelters, trisomy x.
Trisomy 18?
Edward syndrome, heart defects, clenching fists, developmental skills stalled
Anticodon?
A three base sequence on one loop of tRNA molecule that is complementary to mRNA and joins the appropriate amino acid to mRNA
Apoptosis?
A form of cell death that is a normal part of growth and development
Chaperones?
A protein that binds a polypeptide and guides folding
Chromatin?
DNA and its associated proteins
Centromere?
The largest constriction in a chromosome, located at a specific site on each one
Cytoplasm?
cellular contents other than organelles
Enzyme?
A type of protein that speeds the rate of a specific biochemical reaction
Gametic cell?
Sex cell
Genome
The complete set of genetic instructions in a cell
Haploid?
A cell with one set of chromosomes
Diploid?
A cell with two sets of chromosomes
Histone?
A type of protein in which DNA entwines
Nonsynonymous codon?
A codon that encodes a different amino acid from another codon
Reading frame?
The grouping of DNA base triplets encoding an amino acid sequence.
Synonymous codons?
DNA triplets that specify the same amino acid
What kind of cells does mitosis create?
Somatic
What kind of cells does meosis create?
gametic
What phase does DNA replication occur in?
S phase
What happens during G1?
Cell prepares for DNA synthesis
When does cell growth occur?
interphase
what are homologous chromosomes?
Identical pairs of chromosomes