Topic 1 flashcards

2n

symbol for diploid number

Diploid genomes

Most eukaryotes are this due to having homologous chromosomes

Diploid

haploid sets of 2 chromosomes

Visible in karyotypes

Sex chromosomes, extra or missing chromosomes are examples of genetic traits that are _____

Polymer

Set of repeating units

Nucleotide

Unit repeated in polymers of DNA

Sugar

Part of nucleotide attached to phosphate group and and nitrogenous base

Ribose

Sugar with alcohol attached at 2 prime carbon

Deoxyribose

Sugar with hydrogen attached at 2 prime carbon

2’

Carbon to which sugar-defining group is attached

Nitrogenous base

Genetic structure attached to 1 prime carbon. 2 substructures and 5 types

Purine

Double ring nitrogenous base structure

Pyrimidine

Single ring nitrogenous base structure

Adenine, Guanine

Purine bases

Uracil, Cytosine, Thymine

Pyrimidine bases

Phosphate group

Negatively charged structure attached to 5 prime carbon

Chargraff

Scientist who measured ratios of nucleotide bases in dsDNA. Found that A:T and G:C ratios both =1 across species

5’

Carbon to which phosphate group is attached

1’

Carbon to which nitrogenous based is attached. Bonds with nitrogen of nitrogenous base

Franklin

Scientist who x-rayed and laid foundation of DNA structure

Regular

DNA’s structure is ____

2\.0 nm

DNA width

0\.34 nm

Distance between nitrogenous bases

3\.4 nm

Length of DNA

Uracil

Nitrogenous base present only in RNA

Thymine

Nitrogenous base present only in DNA

Watson and Crick

Scientists who proposed double helix structure

1962

Year double helix structure won Nobel prize

Miescher

Scientist who discovered base chemical properties of DNA

Antiparellel

Two strands of nucleotides are arranged in this formation

Backbone

Sugar-phosphate structure that provides support to DNA molecule

Base pair

Grouping of two nucleotides h-bonded at the nitrogenous base

Complementary

Bases must be ______ to allow h-bonding and base pairs to form.

2

Adenine-thymine pairs have this many h bonds

3

Guanine-cytosine pairs have this many h bonds

Weaker

AT pairs are ______ than GC pairs due to having fewer h-bonds.

Pyrimidine

Purine bases only pair with _______ bases and vice versa

Consistent

Pyrimidine-purine pairings have very _______ spacing between them, pyr-pyr and pur-pur do not.

Right-handed

Most common dsDNA helixes are ______

Stability

DNA coils to provide ______ from stacked basis

Primary

Nucleic sequence, molecular structure of DNA is at the ____ level. This is where most genetic differences occur

Secondary

Double helix is the _____ level

Tertiary

How the double helix interacts with itself is the _____ level

Alignment

Putting multiple single strands of DNA sequences together to compare difference between individuals or species in one genomic region

Genomic region

Specific segment of DNA that contains specific gene

Single nucleotide polymorphism (SNP)

One base in alignment is different than all others

Insertion and deletion (INDEL)

One section of the genomic region is present or absent in alignment

B DNA

Most common secondary structure of DNA

Right, 10

B DNA is ___ handed and has ___ base pairs per turn

Right, 10.9

A DNA is ___ handed and has ___ base pairs per turn

A DNA

Secondary structure present when DNA is dehydrated, in dsRNA and in DNA-RNA hybrids

Z DNA

Secondary structure present in GC rich areas or areas of active transcription

Left, 12

Z DNA is ___ handed and has ___ base pairs per turn

Complementarity

Given _______, nucleic acids can pair to themselves in a single strand of DNA or RNA

Hairpin

Alteration of ssDNA/ssRNA when a set of bases are perfectly complementary

Stem-loop

Alteration of ssDNA/ssRNA when a set of bases are perfectly complementary with non-complementary region in between.

Palindromic motif

Set of single strand that is complementary to itself, lends itself to alterations like hairpins or stem-loops

Stability

Secondary structure alterations occur in single strands to add ______

Iterative

Tertiary structure is ____ in order to allow extreme packing of DNA

50000

Scale of tertiary structure packing in eukaryotes

Supercoiling

Type of tertiary structure present in both prokaryotes and eukaryotes. Only type of tertiary structure in prokaryotes.

Topoisomerase

Enzyme that can increase or decrease base pairs per turn by breaking or twisting DNA strands.

Positive

Positive supercoiling causes _______ compacting of chromosomes

Chromatin

DNA and proteins bind to form this

Nucleosome

1st stage of chromatin formation in which DNA wraps around histone proteins

Histone proteins

Positive proteins around which negative DNA winds.

9

Number of histone proteins in a single nucleosome

200

Approximate number of base pairs between nucleosomes

Repetitive

Histones are needed in high numbers and therefore are highly ______

Functional repeats

Repetitive DNA done for products that need extremely high repetition

rRNA, tRNA

Functional repeats other than histones

Tandem

Histone repeats are _____ (present together on genome)

2, 1, 1, 6

In humans, ____ histone repeats are clustered on chromosome ____ , and ___ histone repeats are clustered on chromosome ___

Scaffold proteins

Supercoils of nucleosomes are held together by _______

Genetics

Basis for all traits in all things living

Genome

Complete set of genetic instructions for organism

Eukaryote

Organism cells contain a nucleus

Prokaryote

Organism cell does not contain a nucleus

Complete genome

Most cells in multicellular organisms carry this, even if it is not used

Mammalian red blood cell

Example of eukaryote cell that does not contain a nucleus in order to aid in oxygen and hemoglobin transport

Double stranded DNA (dsDNA)

All prokaryotes and eukaryotes have this DNA structure

Viruses

Can have dsDNA, ssDNA, dsRNA or ssRNA and are not organisms

one dsDNA molecule

Chromosomes are usually this

Genes

Sequences encoding products for cells, in particular spot on genome

Noncoding DNA

Sequences in genome that do not encode products. Some have purpose such as the origin of replication sequence, some have no known function

Prokaryote DNA

Have very high gene density (~1 gene/1k base pairs) and very little noncoding DNA

Linear

Relationship between \# of genes and \# of base pairs in prokaryote DNA

Nonlinear

Relationship between \# of genes and \# of base pairs in eukaryote DNA

1.5%

Genes make up this amount of the typical genome in humans as much of the genome is noncoding DNA

Repetitive sequences

Parts of DNA that are repetitive, inside and out of genes

59%

Amount of repetitive DNA in human genome

Tandem repeats

Repetitive sequence that occurs next to itself

Dispersed repeats

Repetitive sequence that occurs separately throughout genome

Centromere

Thin chromosome region between both arms

P arm

Shorter arm of chromosome

Petite

“P” in P arm stands for

Q arm

Longer arm of chromosome

Telomere

Either end of chromosome

Circular

Chromosome shape in prokaryotes

Linear

Chromosome shape in eukaryotes