Honors Bio Williams s2

Dna Role and Function

store genetic information

*Structure:

Double Helix, 2 polynucleotide

what is dna made up of

Hydrogen bonds, nitrogenous base, deoxyribose sugar, phosphate group

How do cells copy DNA?

S phase, Dna unwinds

helicase, Polymerase

unwinds Dna, makes new strands

replication and mutation

More times a DNA replication, higher chances of mutation

what do enzymes do for dna

Enzymes “proofread” DNA and try to correct mistakes

43 *Central Dogma of Molecular Biology

- DNA>RNA>Protein

Transcription:

copying a DNA gene into RNA

Translation:

converting RNA into amino acids

47 *Three RNA

Messenger, Transfer, Ribosomal

Messenger RNA (mRNA)

Carries genetic information from nucleus to ribosome

RIbosomal RNA (rRNA)

Peptide bonds between AAs, 60% of ribosomes (where polypeptides/proteins are made)

Transfer RNA (tRNA)

Transfers amino acids in the cytoplasm to ribosomes, amino acid holding end, anticodon

49 *Post-transcriptional Modifications

1. 5’Cap: added to beginning of gene

Helps ribosomes recognize start sequence

Prevents mRNA breakdown in cytoplasm

2. Poly-A tail: added to end of gene

Helps ribosomes recognize end of gene and detach

Splicing:

Introns removed & Exons “spliced” together, One gene = more than one protein

*What is the purpose of transcription?

To make a copy of the gene to take to the ribosome for protein synthesis

Where in the cell is the DNA found?

NUCLEUS

Where in the cell does transcription take place?

NUCLEUS

What polymer is synthesized during transcription?

mRNA

What monomers are used to construct this polymer and where are they found?

NUCLEOTIDES, Inside the nucleus

What enzyme (protein that makes reactions happen) is required for transcription?

RNA polymerase

79 *Nondisjunction

When homologous chromosomes fail to separate during Meiosis I or II

*Sickle Cell Disease

carry less oxygen, Hemoglobin is affected by mutation

*Gel Electrophoresis -

separate dna fragments by size, enzymes added to dna to cut it, Large dna fragments are closer to start

Human Chromosomes

- 46 chromosomes, 23 pairs

*Cystic Fibrosis

(autosomal recessive, body makes mucus and clogs

Huntington’s Disease

(autosomal dominant), inherited, break down of nerve cells in brain

(Heterozygote Advantage)

when being a carriers gives you more protection from dieases like malaria and sickle cell

Restriction Enzymes -

cut dna segments

Gregor Mendel’s Contribution -

used the peas as an example, three laws: dominance, segregation, and independent assortment

Segregation of Alleles

- pulling apart allele

Independent Assortment of Chromosome

- random distribution of alleles

Alleles -

version of a gene

Gene -

made up of dna, controls your traits

Punnett Squares -

predict the probability of traits

Incomplete Dominance

- traits are mixed

Codominance -

both show up but not mixed

Multiple Alleles -

more than two possibilities for a trait

Polygenic trait

- human skin color

*PCR

amplify dna sequences

Pedigree chart

trace inheritance genes

Polymerase -

needs taq to withstand temperature without denaturing

Alleles and genes -

alleles r difference form of a gene

Meiosis and genetic diversity -

increases with variety

Cystic fibrosis -

autosomal recessive, has mucus that clogs body

Ribosome

synthesize proteins

Dna negative in gel

, attach to positive

Biological fitness -

ability to survive and reproduce

Recombination dna -

combination of dna from 2 or more organisms, uses restriction enzymes

Gene therapy -

cure genetic disorders by replacing defective genes

CRISPR -

repairs existing abnormal genes

Huntington’s disease

- autosomal dominant, only need one dominant

X-linked recessive disorders -

common in males