Midterm #2 Babu

phosphate, sugar, nitrogenous base

DNA is a chemical component for herdity

come up with Chargaff base properties

DNA has equal amount of As/Ts and Gs/Cs

calculates diffraction patterns.

Expert in areas of constructive and deconstructive diffration patterns

Radioactive interferance

Works w Rosalyn Franklin on diffraction patterns. Unable to calculate back to structure of DNA molecule from that.

top 5’ to 3’

bottom 3’ to 5’

where is most of the DNA in the nucleus stored

functional units of sequences of chromosomes

DNA encodes information. Kept safely in the vault

Small sectional copies are made: RNA

RNA exits to the cytoplasm (rough neighborhood)
RNA translates material to make amino acids (proteins)

Transcription changes the nucleic acid language like a dielect of a language (British vs American English)

Translation completley changes the language to make proteins

A → U

C → G

G → C

T → A

A→ U

C → C

G → C

U → A

The extra oxygen it carries increases polarity and therfore its attraction.

RNA polymerase(RNA enzyme) makes a copy of one gene from DNA template as hnRNA molecule

3 stages: Initiation, Elongation, Termination

heterogenous Nuclear RNA.

Unprocessed mRNA.

encompasses various types and sizes of RNA

First phase of RNA

The growing end of RNA

The hanging off bit in RNA

3’ to 5’

Opposite the nucleotide (DNA)

5’ to 3’: RNA would be 3’ to 5’

Bottom DNA 3’ to 5: RNA would be 5’ to 3’

1. Initiation

2. Elongation

3. Termination

Stage 1 of transcription.

RNA polym. binds to promoter and opens DNA helix

RNA synth begins.

Comes and reads the 3’ to 5’ strand.
→Makes 5’ to 3’ RNA

Upstream of the gene in DNA. Where RNA bind to initiate transcription of that gene

Stage 2 of Transcription

DNA threaded through RNA polym. (like a zipper)

RNA strand gets longer, thanks to the addition of new nucleotides.

Stage 3 of Transcription

RNA polym. reaches a bump in terminator region and falls off

Now it is hnRNA

a mRNA that encodes several proteins and is characteristic of many bacterial and chloroplast mRNAs

After transcription

mRNA created from hnRNA so it can be fully functional (mature)

Caps and tails are added

Introns removed in splicing and exons stitched in

non coded nucleotide

transcripted but not translated

removed in RNA processing

Vital in genes, non vital in RNA

Complete info for protein

Stitched in in RNA processing

Occurs during RNA processing

Introns removed

Exons stitched in

Another level of regulating gene exporting —> increased chance of cell survival

• Only in eukaryotic cells

• maybe this explains the diverse organisms from eukaryotes

After transcription and RNA processing

RNA going from Nucleic Acid —> Amino Acid (TRANSLATNG the language)

rRNA and tRNA

4 stages:

1. Initiation

2. Elongation

3. Translocation

4. Termination

contains instructions for cells to make proteins

made after rna processing once introns out and exons in

Ribosomal RNA: Major Component of ribosomes (organelles that make proteins)

Transfer RNA: “interpreters”

Read mRNA code

Insert amino acids to growing proteins

Looks like a 4 leaf clover

Hydrogen bonds between pairs

64 total. 61 have AA, 3 are stop

4 leaf clover characteristic

64 possible (-3 stop)

Degenerate (code stops mattering as you move down)

AUG

UAA

UAG

UGA

Ribosomes export mRNA (nucleus→ cytoplasm) and translate it

Nucleic Acid code in mRNA is translated into amino acids to synthesis polyptides (small part of a protein)

• mRNA Nucleic acid language translated by ribosomes to Amino Acid langauge

Ribosome binds mRNA and tRNA

ribosomes catalyze (efficiently form bonds) between AA in A and P site

• ribosome continues to translate each codon

ribosomes move over one codone and leet other ribosomes in

• RNA= freeway

• Ribosomes= cars on freeway

Steps 2/3 (Elongation and Translocation) repeated over and over

Steps 2/3 (Elongation and Translocation) repeated over and over

Stop codone reached

Release factor binds the ribosomes

Complex falls off

the process by which the information encoded in a gene is turned into a function

DNA availability and nuclear export

How long RNA stays in cytoplasm affects hoe a gene is expressed.

Short RNAs go quicker and faster (quantity), while long tailed RNAs last for a longer time and make more protein (quality)

Change to a DNA

Can alter polypeptide folding causing genetic disorders

• alzheimers and cystic fibrosis

Substitution, insertion, deletion

Change reading frame of DNA through insertion or deletion

Destroys the gene

protein refolding disease that has evolved to avoid cell’s defense against them

proteins refold and change 3d shape

either makes a dead or rogue protein

• mad cow disease

growth and development, reproduction

A sex cell. One is contributed by each parent in sexual reproduction

Fertilized egg cell that results from a male and female gamete

Mieosis: Each parent contributing a gamete (fertillization) to create a zygote

Mitosis: Each cell cloning itself over and over to produce an offspring

Creates a unique gamete

Regenerates/clones cells

Targets weak or decayed cells for cel death.

Programmed cell death

semi-conservatively:

replication of one parental strand to give its complementary strand, AND the replication of the other parental strand to give its complementary strand

all chromosomes/genes of an organism

used in DNA replication to weld DNA shut

Unwinds DNA at origin of replication

builds new DNA (5’→3’) off of each template strand

DNA polymerase

If the polymerase detects that a wrong (incorrectly paired) nucleotide has been added, it will remove and replace the nucleotide right away, before continuing with DNA synthesis .

An Error repair mechanism conducted by DNA polymerase

• only 1/billion nucleotides is wrong

• mutations due occur

  • worst ones are mutations to proofreading

DNA repair after DNA replication and proofreading. Any mistake after this is a mutation

the process of asexual reproduction

1. DNA replication

2. Separate chromosomes

3. Move to opposite side of cell and stick to membrane

4. Cell membrane split into two

Binary fission (Mitosis)

The most condense state of DNA

How 6 ft of DNA is packed into each nuclei

Chromatin wound into very tight fibers of nucleosomes

threadlike structure of nucleic acids and protein found in the nucleus

Chromatin

DNA and histone proteins (binding and shaping agent for DNA)

much more effort for cell reproduction

Very similar but same variation (vs completely the same)

same gene , different flavors of same gene

• each have the same genes in the same order, but there may be variation between them, resulting in different alleles

chromosome at most compact state (really just a compact chromosome)

one of the two identical halves of a chromosome that has been replicated in preparation for cell division

2 chromatid identical copies of a chromosomes that is joined with it’s other chromatid at the centromere

having a single set of unpaired chromosomes.

The presence of two complete sets of chromosomes in an organism’s cells

Each parent contributes a chromosome to each pair

Never divide

Interphase

RNA, proteins, and other molecules are made

Gap 1

DNA is replicated

Synthesis

Preparing for cell division

False, some stay in G1 or permanently in G0 and never divide

division of chromosomes

division of cytoplasm; splitting into 2 cells

Prophase

Prometaphase

Metaphase

Anaphase

Telophase

PROtects the DNA with supercoiling: chroms condense into 2 chromatids

chromosomes move to opp sides of nucleus

nucleus breaks down

spindle fibers attach

chromosomes with spindle fibers attached move to the metaphase plate (midline, spindle equator…)

Centromere divide to convert each sister chromatid into a chromosome

Nuclear envelope reforms and DNA decondenses

Diploid (2n)

• 23 pairs, 46 total

Habloid (n)

• each gamete has 0 pairs, 23 total

Mieosis. Gametes fuse.

• each gamete has 0 pairs, 23 total (n)

• Together become 23 pairs, 26 total (2n)

ONE Diploid cell (2n) undergoes replication

Chromosomes not replicated, but split

TWO habloid cells (2xn) are yeilded

• ½ as many chrom. per cell —> (n)

crossover events occur

Homologous combination

New genetic material created. These genes affect the same area, but may be different

• ex: hair gene crossover yeilds dominate black over recessive blonde

start with TWO habloid cells (2xn)

produces FOUR habloid cells (4xn)