Genetics (Semester 3) (Term 1)

Gene

A segment of DNA that contains an assortment of nucleotides which controls the phenotypic expression of an organism through controlling protein or RNA production which can be pass down from parent to offspring

Organelles that contain DNA and RNA in plants

Chloroplasts, Mitochondria, and Nucleus

Organelles that contain DNA and RNA in Animals

Mitochondria and nucleus

Purines

A double ringed nitrogen bases that exist on DNA and RNA, specifically adenine and guanine.

Pyramidine

A single ringed nitrogen base that exists on DNA and RNA, specifically Cytosine and Thymine (DNA) / Uracil (RNA),

Uracil

A pyramidine base that replaces Thymine in RNA due to a smaller molecular weight to prevent overloading the single strain structure of RNA.

Nucleotide

An organic molecule comprised of a nitrogen base attached to a ribose sugar with a phosphate group. A monomer of Nucleic acid.

Nucleic Acid

A long unbranching chain of nucleotides connected by a phosphate group and ribose sugars forming a backbone.

Nucleoside

The part of the nucleotide that is made of ribose sugar and nitrogen base.

Cell cycle replication type

Semi-Conservative Replication

Semi-conservative replication

A type of replication theory that insists that an DNA is split into two and the new DNA strands produced maintain one old strand and one new strand.

G1 Phase

The first phase of interphase, the cell grows larger after splitting in the mitosis phase

S phase

Second phase of interphase where the DNA in the nucleus undergoes replication which effectively doubles the amount of DNA in the cell.

G2 phase

Final phase of interphase that prepares the cell for mitosis by increasing its size.

Prophase

The first phase of mitosis where the nuclear envelope starts to dissolve, spindles start to form and DNA condenses into chromosomes.

Prometaphase

Second phase of mitosis where the nuclear envelope breaks down completely and the spindles attach to the chromosomes.

Metaphase

The third stage of mitosis where the chromomsomes line up in the equator of the cell.

Anaphase

The fourth stage of metamorphosis where the spindle fibers attach to the separate sister chromatids.

Telophase

Final stage of mitosis where sister chromatids are condensed in the poles of the cell as a nuclear envelope starts to reform before the cell splits into two.

coding strand DNA

5’ to 3’ strand of DNA that responds to the nitrogen bases of the template strand

Template strand

3’ to 5’ strand of DNA that responds to the nitrogen bases of the coding strand

mRNA

RNA strand that attaches to the template strand and encodes its opposite codon. Similar to the coding strand but Thymine is replaced with Uracil. mRNA travels outside of the nucleus to attach to a ribosome.

tRNA

RNA that carries amino acids to the ribosome that responds to the anti-codon in the mRNA.

Start Codon

Metionin / AUG

Stop Codon

UUA, UGA, UAG

Exons

Part of the DNA that encodes genetic information that is condensed into mRNA in RNA splicing

Genome

A set of chromosomes that exist within double membrane organelles.

Metacentric

p arm and q arm are equal in length

Submetacentric

p arm is slightly shorter than the q arm

Acrocentric

p arm is signififcantly shorter than the q arm

Telocentric

there is no p arm

Oogenesis

process of producing female gamete, mitosis and subsequent meiosis of oogenia to form an ovum (n) and two polar bodies (n)

Oogenia

Diploid cell that undergoes meiosis in oogenesis

Primary oocyte

A diploid cell that is the product of mitosis of Oogenia

Secondary oocyte

A haploid cell that is produced through the Meiosis I of the primary oocyte

Ovum

Haploid cell produced by meisosis II of the secondary oocyte

Polar bodies

haploid cells that are a byproduct of Meiosis I and II

Spermatogenesis

Process of male gamete production; Mitosis and subsequent meiosis of spermatogonia to produce 4 functional sperm cells

Spermatogonia

Diploid germ cell that undergoes mitosis to form 2 primary spermatocyte

Primary Spermatocyte

Diploid cell that undergoes meiosis I to form 2 secondary spermatocytes

Secondary Spermatocyte

Haploid cell that undergoes Meiosis II to form 4 spermatids

Spermatids

Haploid cells that are further differentiated into sperm cells

Sperm

A haploid male gamete that carries half of the normal human chromosome number (n=23) and either carries an X or Y gonosome.

Ovum

A haploid female gamete that carries half of the normal human chromosome number (n=23) and either carries and X or Y gonosome.

Allele

An alternate form of a gene that occupy the same locus

Homologous Chromosomes

Chromosomes that possess two representative of the same gene

Homozygous

both alleles are identitcal

Heterozygous

allleles are different

Dominant trait

An allele that completely overrides the phenotypic expression of that particular locus

Recessive trait

An allele that is only phenotypically expressed in homozygous pairs with itself

Phenotypic ratio of complete dominance Dihybrid cross

9:3:3:1

Phenotypic ratio of incomplete Dominance Dihybrid cross; Genotypic ratio of Dihybrid cross

1:2:1:2:4:2:1:2:1

Phenotypic ratio of incomplete dominance monohybrid cross; genotypic ratio of monohybrid cross

1:2:1

Phenotypic ratio of complete dominance monohybrid cross

3:1

Reciporal cross

A cross reversing the genotype of the male and female parent to confirm previous results

Back cross

A cross of an F1 individual with either of its parents

Test Cross

A test that crosses an individual with a dominant phenotype but an unknown genotype with an individual with a recessive phenotype and genotype.

Lethal gene

An allele that will literally kill the organism if the allele is in a homozygous pairing but displays a trait in heterozygous pairs; 2:1 ratio of impacted : normal