BIOB11

DNA to RNA to Protein

Determines the phenotype

Same copy (AA or aa)

Different copy (Aa)

An Individual’s two alleles segregate from one another during gamete formation

Segregation of a pair of alleles for one trait has no effect on the segregation of alleles for another trait

Discovery of chromosomes

Concept of homologous chromosomes

Homologous chromosomes when paired (bivalent) can break and exchange pieces with each other to allow for reshuffling of genes

Point at which homologous chromosomes are crossed

Rosalind Franklin’s X ray diffraction image of DNA in 1952 was key to figuring out the double helix model

Cytosine, Uracil, Thymine

Guanine, Adenine

Connects nucleotides

hydroxyl

phosphate

[A] = [T] and [G] = [C]

1. Storage of Genetic Information

2. Replication and Inheritance

3. Expression of Genetic Message

Membrane-enclosed Nucleus

No distinct nuclear compartment

Portions of DNA found in a condensed form

Do not code for proteins

Protein-coding sequences

Removes introns from RNA

mobile elements that can move around in the genome and duplicate themselves, leading to repetitive sequences

Double-stranded, double helix DNA molecule twists on itself

Helix is __over__wound

Helix is __under__wound

Highly conserved proteins rich in basic amino acids

Eukaryotic DNA associates with histones and other proteins to form chromatin that forms chromosomes

Repeating subunits of negatively supercoiled DNA + 8 histones

Lowest level of chromatin organization

Level of chromatin organization above nucleosomes

Made of histone H1 + core nucleosome

Linker histones - binds linker DNA that connects one nucleosome to another

Supercoiled loops of 30 nm fiber

Less compacted, functionally active sections of DNA

Always compacted, little to no functional activity sections of DNA

Compact at all times, surrounds telomeres and centromeres, contains DNA repeats and relatively few genes

Inactivated during certain phases of organism’s life

Inheritance that can occur without changes to nucleotide sequence in DNA

Acetylation leads to more open structure and transcription

Methylation leads to less

acetylates proteins

removes acetyl group from proteins

adds methyl groups to lysine or arginine

Removes methyl group

Silencing of genes by heterochromatin occurs in regions and is inherited after cell division

proteins that bind to methylated DNA can recruit enzymes involved in promoting a repressed chromatin state

C-phosphate-G

Epigenetic marker created by DNA methylation

some methylation patterns are passed on to offspring

Protein complex that “reads” the histone code and positions and activates enzyme “writers” that can act on the DNA/histone

Create physical barriers or actively recruit opposing chromatin modifying enzymes

Switching one nucleotide for another

DNA that repeats themselves over and over without interruption

5-500 bp in tandem repeats of up to 100 kb

10-100 bp with up to 3k repeats

1-5 bp in clusters of 10-40 bp scattered evenly throughout genome

Regions of repeated DNA that change in length when mismatch repair is not working properly

Usually in euchromatic regions, predisposed to large mutations

common in pericentriomeric or subtelomeric regions

Blocks of DNA in conserved order

DNA that moves from one place to another in the genome

Used by Transposable elements with LTRs (long-terminal repeats) to copy themselves

Required for recognition by transposase and excision from donor DNA

Generated in recipient DNA

“copy-and-paste” mechanism that involves an RNA intermediate

Transposition altering gene sequences

Mutation of a gene in an ancestral organism causes speciation and gives rise to two separate species

Gene duplication and divergence within the same species

Misalignment in two genes causing deletion in one gamete and duplication in the other

Closely related sequences which may encode related polypeptides that have a similar function

“Genes” that have a similar sequence to their gene family but have accumulated so many mutations that they are now non-functional

Single nucleotide difference in protein coding/non-coding sequence, causes alleles

Difference in the number of copies of a particular sequence

Changes in segments of the genome that alters chromosome structure

A particular combination of alleles on a chromosome that are inherited together

Higher the G/C content, higher the Tm

G/C has more h-bonds and more base-stacking interactions

Smaller the genome, the faster

points where a pair of replicating segments come together and join the non-replicated segments

Opens up DNA double helix ahead of replication fork

Bind and stabilize single stranded DNA after helicase unwinds double helix

Family of enzymes that carry out new DNA synthesis

Synthesized by primerase, required to by DNA Polymerase to being synthesis

generates temporary single-strand breaks in DNA to relieve torsional stress of DNA unwinding

‘Nicks’ one DNA strand to allow free rotation of DNA

Catalyzes a double stranded break to detangle DNA

Removes incorrectly added nucleotide

Distortions of the double-helix are used for recognition of mismatched base-pairing

Small fragments that are synthesized into the lagging strand

Covalently connects the Okazaki fragments into a continuous strand

Clamps DNA Polymerase onto DNA template during synthesis

DNA Synthesis Phase

Adds back histones to re-established nucleosomes behind the replication fork

Eukaryotic cells replicate their DNA in small portions

Sequences at the end of chromosomes that are composed of tandem repeats

Extends the template strand with repetitive DNA

Removes base from DNA

Most commonly converts cytosine to uracile

Removes bulky lesions

repairs DNA being actively transcribed

repairs DNA in the remainder of the genome

Cut the damaged strands on either side of the lesion (as separated by DNA helicase)