Terminology Review Flashcards
Genome
Entire halpoid set of heritable Material found in a cell or organism
- usually DNA – sometimes RNA
Chromosome
Organized structure of DNA containing all or part of the genetic material of an organism
Chromatin
The substance of a chromosome containing DNA + protein
Chromatid
One half of a replicated Chromosome
Eurochromatin
Loosley packed forms of chromatin
***Light bands
Heterochromatin
Tightly packed forms of chromatin
***Dark bands
What makes up a chromosome
Chromatin (Chromatin = DNA + Protein)
Chromatid
A replicated chromosome prior to recombination and or cell division
Sister chromatids
Within the same replicated chromonome
Non-Sister chromatids
Found on homlogous chromsome
Chomosome termnonlogy image
DNA
Deocyriobonucleic Acid – hereditary materia
ssDNA
Single Stranded DNA
nDNA
Nuclear DNA – DNA found in the nucelus
***nDNA = typically contains multiple chromosomes
mtDNA
Mitocondrial DNA – DNA found in the mitocndria
cpDNA
Chloroplast DNA – DNA found in the chloroplast
Chomosomes in bacteria + Viruses + mtDNA = cpDNA
Bacteria + Viruses + mtDNA = cpDNA = tyically contain a single chromsome AND the complete unit of DNA in tehse organeeles/organsims are pften referd to as the bacterial + viral + mirocondrial + chlorplastal genomes
What is included when refer to Eukaryotic genome
technically the complete genomes includes nDNA + mtDNA + cpDNA BUT when someone is talking about the Eukaryotic genome they are typically refering to nDNA only
Gene
Heretible unit that contributes to a charachteristics – often encodes protein BUT can also encode RNAs
***segment of DNA that contributes to charachteristics –> usually Protein coding regions
Coding DNA
regions of genome that represent protein coding sequences
What does gene refer to
The term gene can refer to the coding sequence only OR the coding sequence and the regulatory sequences that are proximal to the coding sequence
Allele
A version or variant of a particular locus on the genome
What does allele refer to
Often refer to gene variants BUT can also refer to variation in DNA sequences at any position on the genome (even in non-coding regions)
Allele Names
Can be anything as long as they are defined
Types of alleles
- Wild-Type
- Mutant
- Null
Wild-Type allele
One of many possible alleles of a gene that allo wthe gene to function “normally”
***Normal can be context specific
Mutant Allele
Allele that results in abnormal function of a gene
***Can also refer to scenerios where reserachers are monitoring changes (mutation) in DNA whether they are involoved in gene function or not
Null Allele
An Allele that results in either no gene product being produced or the absence of function of the gene product at the phenotypic level
Genotypes for a locus in diploid organisms abbreviation
+/+ – indicated 2 W-T alleles
+/- – indicates 1 W-T and 1 Null allele
-/- – indicates 2 Null alleles
Locus
A specific position on a genome
Phenotype
Observable charachteristics
Genotype
Combination of alleles for a particular individual
Chromosome Number (N)
Refers to the number of unique nuclear chromsomes in a cell or organsims
***Excludes mtDNA + cpDNA
Ploidy
The number of sets of chromsomes in a cell
Example – halpoid 1N OR diploid 2N
Homologous Chromosomes
Chromosomes that share similar structural features and genes – inherited from each parental source
Alleles on Homologous Chromosomes
Homologous Chromosomes can have different alleles
What types of organisms have homologous chromosomes
Only organsims thar are >2N (diploid or higher) have homologous chromosomes
Karyotype
An individual’s collection of chromosomes
Homozygous vs. Heterozygous
refers to the state of an individual with identical or non-identical alleles at a particular locues
+/+ VS. -/- VS. +/-
Homozygous
Two of the same allele
AA or +/+ or -/-
Heterozygous
Two different Alleles
Aa or =/-
What is common feature of chromosome in Prokaryotes
Circular + Smaller than Eukaryotes
What is the order of DNA from the least condenced to the most
Nucelosome –> 30nm fiber –> 30 nm loop –> 250 nm fiber –> 700 nm fiber
***Check this
Gene expression is most likley to occur in…
Eurochromtin – Logical because it is looke = transcription/translation can occur
Directionality of FISH probes
Probe – 5’-3’
DNA – 3’-5’
What type of variation is obseirved in this chromsome (one was longer than another)
Heterochromatin + Eurochromatin differences
A gene, BING-GB, contributes to the development of green blood and is located on the p arm of the metacentric chromosome 16. Individuals with the GBa allele are more likely to develop green blood than individuals with GBb allele. The BCA gene, located on q arm of the submetacentric chromosome 7, is involved with affinity for bearcats. Individuals with the BCA1 allele are more likely to love bearcats than individuals with the BCA2 allele. Consider an individual that is heterozygous for both loci. Which of the following depicts the relevant chromosomes following G1 phase of the cell cycle.
