Biology SBI3U1 - Genetics

Polymer

Long molecule of repeating units called nucleotides.

Nucleotide

Unit made up of a phosphate group, sugar (deoxyribose or ribose), and a nitrogen base.

Watson and Crick

"Discovered" the first model of DNA; Won the Nobel Prize.

Franklin

Her experimental data was used by Watson and Crick when they created the model of DNA.

Nitrogenous bases

A - Adenine; T - Thymine; G - Guanine; C - Cytosine; RNA - U - Uracil instead of Thymine.

Hemoglobin

Carries Oxygen in your blood cells.

Meiosis

Cell division that produces sex cells (eggs, sperm); 2 divisions, one round of DNA replication.

Gametes

Reproductive cells, haploid: half as many chromosomes.

Genome

All the DNA in a cell.

Somatic

Body cells, diploid, 2 sets of chromosomes.

Centromere vs. Centriole

Centromere → holds 2 chromatids together; Centriole → organelle that produces spindle fibers.

Chromatin vs. chromosome vs. chromatid

Chromatin: packaged DNA; Chromosome: condensed DNA; Chromatid: two identical copies of chromosomes (sister chromatids).

Karyotype

Visual representation of a person's genome.

Mutagen

Causes errors in DNA.

Malignant vs. benign

Malignant - invade surrounding tissues → cancerous and can metastasize; Benign - non-cancerous but can impede on daily living.

Metastasize

Spread of malignant tumors.

Gonad

Reproductive organs → testes, ovaries.

Zygote

Formed from the fertilization of gametes from 2 parent cells.

Homologous Chromosomes

Pairs of chromosomes one from each parent.

Haploid vs. Diploid

Haploid → half the number of chromosomes (n); Diploid → 2 sets of chromosomes (2n).

Synapsis

Pairing of homologous chromosomes.

Crossing over

Segments of chromosomes may be exchanged; Provides genetic diversity.

Independent Assortment

Random arrangement of homologous chromosome pairs which increases variation.

Spermatogenesis

The process of sperm production in the testes.

Oogenesis

Egg production in ovaries.

Polar Body

Small cell that becomes recycled waste; Not a viable egg.

Allele

A different version or form of a gene.

Autosomal

Genes and traits located on any of the 22 numbered pairs of chromosomes (autosomes) in a human cell, excluding the sex chromosomes.

Heterozygous

A term that describes having two different versions of the same gene; Two different alleles.

Homozygous

Having two identical alleles of a particular gene or genes.

Genotype

The genetic makeup of an organism; The allele combination.

Phenotype

The set of observable characteristics; Description of allele combination.

Mendel’s Law of Segregation

During the production of gametes, two copies of each hereditary factor segregate so that offspring acquire one factor from each parent.

Mendel

Discovered the basic principles of heredity and laid the mathematical foundation of the science of genetics.

Nondisjunction

The failure of one or more pairs of homologous chromosomes or sister chromatids to separate normally during nuclear division.

Trisomy

A condition in which an extra copy of a chromosome is present in the

Gametes

A sex cell (sperm or egg)

Chromosome

Threadlike structures that carry genetic material

Gene

A segment of DNA found on a chromosome coding for a particular trait (ex: eye colour)

Trait

A particular version of a characteristic that is inherited (ex: blue eyes)

Allele

A specific form of a gene. Your cells have two alleles for each gene (one from each parent).

Homozygous

When an individual has two of the same alleles for a given characteristic.

Heterozygous

When an individual has two different alleles for a given characteristic.

Genotype

The genetic makeup of an individual; whether they are heterozygous or homozygous.

Phenotype

An individual’s outward expression of their genes; what trait they show.

Dominant Allele

An allele where, if present, it is always expressed (e.g., brown eyes).

Recessive Allele

An allele that is only expressed in the absence of a dominant allele; must be homozygous recessive for this trait to show (e.g., blue eyes).

P Generation

The parents used in a cross.

F1 Generation

The offspring of a P generation cross.

F2 Generation

The offspring of an F1 generation cross.

Test Cross

Crossing an F1 generation with a homozygous recessive individual to determine whether the F1 is homozyg

What is heredity?

the passing of traits from parents to offspring

What is genetics?

the scientific study of heredity

What are traits?

Factors that control traits

What are phenotypes?

physical characteristics of organisms

What is a dominant allele?

an allele whose trait always shows up in the organism

What are alleles?

the different forms of a gene

What is a Punnett Square?

a chart that shows all the possible combinations of alleles that can result from a genetic cross

What is codominance?

inheritance pattern in which the alleles are neither dominant nor recessive

What are sex-linked traits?

alleles passed from parent to child on a sex chromosome.

What is meiosis?

process by which sex cells are created

What is an embryo?

Fertilized egg that has undergone up to 8 weeks of development

Who is known as the father of genetics?

Gregor Mendel

What is a pedigree?

chart that tracks which members of a family show a trait

What is multiple alleles?

Three or more forms of a gene that code for a single trait are called

What is phenotype?

an organism’s genetic makeup, or allele combinations

What is the likelihood that a particular event will occur?

probability

What is cloning?

a method of reproduction that produces a genetically identical copy of an organism.

What is a zygote?

a fertilized egg

What is fertilization?

the process of combining male and female gametes to form a zygote

What is DNA?

a molecule containing genetic information

What is a gene?