BIO BIO BIO

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Who was the first to study inheritance? What was his term for genes?

Mendel, Heredity factors

Genotype

 allelic genetic make up

Phenotype

Observable physical expression of genes

Dominant

every generation shows the trait

Homozygous

two identical alleles for a trait

Heterozygous

different alleles for a given gene

Codominant

AB blood types and O caused by multiple alleles

Incomplete dominance

see 3^rd trait, no dominant trait

Polygenic inheritance

height in humans, continuous variation

Pleiotropy

sickle cell, cystic fibrosis, affects others

Sex-linked

traits controlled by genes located on X chromosome

Autosomal

chromosomes 1-22

Karyotype

picture of chromosomes

Cross a homozygous dominant purple flower plant with a recessive white flower plant to the F2 generation

Phenotypic ratio 3 purple:1 white

Using the above information and R=round seeds, r=wrinkled seeds. Cross 2 double heterozygotes.  What is the phenotype and ratio?

Gamete combos: PR, Pr, pR, pr 9:3:3:1

What can a pedigree explain?

X-linked, dominant if seen in all generations

What is a genetic map?

Distances between gene loci measured in terms of recombination frequency

What is independent assortment?

During meiosis, homologous chromosomes separate.

When will allele pairs assort independently of one another?

When on different chromosomes

What is crossing over?

Genetic exchange between 2 homologous chromosomes

What is nondisjunction?

Chromosomes fail to separate during meiosis, abnormal number of chromosomes

Turner syndrome

monosomy X

Klinefelter syndrome

XXY

Down syndrome

trisomy 21

Name disorders that are found on the X chromosome. Dominant or recessive?

Hemophilia & colorblindness, recessive

What is Huntington’s disease?

Dominant, neurodegenerative that appears in midlife after kids Cystic fibrosis

What is the SRY gene?

Maleness, if deleted then female

Where does your mitochondrial DNA come from?

Mother, all siblings have same mtDNA

What are SNPs used for?

Forensics, distinguish between 2 suspects

What is the central dogma of biology?

DNA  RNA  proteins

Name the 2 main steps of gene expression and where in the cell each occurs.

Transcription (nucleus) & translation (cytoplasm)

tRNA

carry amino acids to ribosome

miRNA

binds directly to mRNA to prevent translation

Splicing

removing introns, addition of poly A tail, 5’ cap

What is a codon?

3 bases of mRNA, codes for an amino acid, blocks of info

Pro Translation and Transcription

translation of mRNA begins before transcription is complete and no introns or exons.

Euk Translation and Transcription

transcription and modification of mRNA is complete before translation begins.

What enzyme performs transcription?

RNA polymerase II

For eukaryotes, what is needed for the transcription initiation complex?

Binding of transcription factor to TATA box, recruitment of more TF and polymerase II

What occurs to a protein if the DNA is mutated?

May alter so that it no longer functions.

Nonsense

stop, shortens protein

Where do DNA-binding motifs interact with a DNA molecule?

Major groove of DNA helix

What is an operon?

cluster of functionally related genes that are regulated together, encode single mRNA molecule

List the order of gene locations in an operon

 Regulatory genes, promoter, operator, genes

Which cells contain operons?

prokaryotes

What would occur if there was a mutation in the lac repressor?

Would waste energy producing enzymes in the absence of lactose.

What would occur if there was a mutation in the lac operator?

Repressor may not bind Promoter? Polymerase would not bind

Why are trp operons needed in a bacterium?

 Make tryptophan

What are nucleosomes?

Histones that are tightly wound with DNA, basic unit of chromatin

Where are enhancers found in relation to a gene?

Upstream from a gene

If DNA has methylated histones, what does that indicate?

inactive

If a protein is unbiquinitinated, what does that indicate?

Targeted for degradation

To degrade mRNA, what must be done to the mRNA?

 Remove 5’ cap, remove poly A tail, 3’ end recognition sites