Honors Biology Units 5-7

Final Exam

Gregor Mendel

Austrian monk who used pea plants to learn about genetics; known as the 'Father of Genetics.'

Law of Dominance

A dominant (strong) allele will express itself over a recessive (weak) allele.

Law of Segregation

When chromosomes separate in meiosis, each gamete (egg or sperm) will receive only one chromosome from each pair.

Law of Independent Assortment

The assortment of chromosomes for one trait doesn't affect the assortment of chromosomes for another trait.

Purebred

Type of organism whose ancestors are genetically uniform.

Monohybrid Cross

A genetic cross involving a single trait, such as crossing a homozygous recessive plant with a homozygous dominant plant.

Parent's Genotypes (Monohybrid)

rr, RR

Genotypic Ratio (Monohybrid)

100% Rr

Phenotypic Ratio (Monohybrid)

100% round seeds

Dihybrid Cross

A genetic cross involving two traits, such as crossing two tomato plants that are both heterozygous tall (Tt) / red (Rr).

Phenotypic Ratio (Dihybrid)

9:3:3:1

Probability in Genetics

Multiplying all of the possible outcomes for larger combinations of alleles.

Genes

Section of DNA that provides the instructions for making a protein.

Alleles

Different versions of the same gene.

Homologous Chromosomes

The matching chromosomes from our mom and dad containing the same genes in the same locations, but may contain different alleles.

Homozygous

2 of the SAME alleles (Ex. AA or aa).

Heterozygous

2 DIFFERENT alleles (Ex. Aa).

Dominant Allele

If present, allele will always have that trait expressed (seen).

Recessive Allele

Allele will only have that trait expressed (seen) when the dominant allele is NOT present.

Genotype

The actual alleles inherited (Ex: FF, Ff, or ff).

Phenotype

The physical traits/characteristics seen in an organism (Ex: Purple flowers).

Punnett Square

A diagram that shows the probability of inheriting traits from parents with certain genes.

Monohybrid cross

a cross between two organisms looking at one trait.

Dihybrid cross

Used when finding the possible genotypes for offspring when considering two traits at the same time.

Cross

mating of 2 organisms

P

parental generation

F1

first generation

F2

second generation

Incomplete dominance

occurs when neither allele is completely dominant nor recessive. The heterozygous phenotype is a combination somewhere between the 2 homozygous phenotypes.

Codominance

occurs when both alleles are fully and separately expressed.

Multiple allele inheritance

refers to a situations in which a single trait is controlled by multiple alleles.

Polygenic inheritance

refers to a trait produced by 2 or more genes, usually with a range of phenotypes that can also be subject to outside influences from the environment.

Blood type

determined by A, B, and i alleles.

Linked genes

are physically located on the same chromosome and will be inherited together (unless separated during crossing over).

Sex-linked traits

are traits controlled by genes on sex chromosomes.

Chromosome Theory of Inheritance

Genes are located on chromosomes and the behavior of chromosomes during meiosis accounts for inheritance patterns.

Epistasis

When one gene overshadows all the others.

Carrier

Someone who carries the recessive trait, but doesn't show it due to having a dominant trait to mask it.

Somatic mutations

occur in somatic (body) cells and are passed on by mitosis → cancer.

Germ line mutations

occur in germ line cells that give rise to gametes and are passed on by meiosis → mutated offspring.

Gene mutations

happen during DNA replication and cause a change to the original DNA sequence.

Chromosome mutations

often happen during meiosis, changing the number or location of genes.

Point mutations

a type of gene mutation that involves a change in a single nucleotide.

Frameshift mutations

involve the insertion or deletion of a nucleotide in the DNA sequence.

Point mutations

Substitute ONE nucleotide for another.

Frameshift mutations

The insertion or deletion of a nucleotide.

Autosomal Recessive

Most common inheritance pattern for genetic diseases; disease is rare in the family, skips generations, and affects males and females equally.

Autosomal Dominant

Disease is common in the family, does not skip generations, and affects males and females equally.

Sex-Linked Recessive

Disease is rare in the family, often affects males more than females, and skips generations.

Mutation

Any change in DNA (the order of nucleotide bases/letters).

Mutagen

Chemicals that can cause DNA mutations, such as radiation, UV light, and cigarette smoke.

Duplication

Changes the size of chromosomes and results in multiple copies of a single gene.

Translocation

Pieces of non-homologous chromosomes exchange segments during crossing over.

Nondisjunction

Chromosomes do not separate correctly during anaphase, resulting in 1 or 3 chromosomes rather than 2 per cell.

Pedigree

Chart used to trace the phenotypes and genotypes in a family to determine whether people carry diseases or traits.

Personal genome sequencing

Using DNA sequencing technologies to have YOUR personal genome sequenced.

Gene cloning and bacterial transformation

A method of genetic engineering involving the replication of genes in bacteria.

Gene therapy

A technique that modifies genes to treat or prevent diseases.

CRISPR

A technology that allows for precise editing of DNA.

Stem cells

Undifferentiated cells that can develop into various cell types.

Selective breeding

The process of breeding plants and animals for specific traits.

Hybridization

The process of crossing different species or varieties to produce hybrids.

Biotechnology

Refers to any technology used to change the genetic makeup of living things to make products.

Societal Implications of Genetic Engineering

Better diagnosis and treatment of diseases, alteration of affected genes, production of pharmaceuticals, and environmental cleanup.

Production of antibiotics

The creation of substances that inhibit the growth of bacteria.

Genetic engineering

The direct manipulation of an organism's genome using biotechnology.

Recombinant DNA

Artificially made DNA from 2 or more different sources.

Genome

An organism's complete set of DNA; all of its genes.

Human Genome Project

The first complete map of the entire human genome, completed in 2003.

ENCODE project

Launched as a follow up to the Human Genome Project to interpret the sequence determined from the HGP.

1000 Genomes project

An even more detailed genome map, sequencing over 1000 different people from a variety of ethnic backgrounds, completed in 2015.

Gene Map

Shows the location of genes on a chromosome.

Restriction enzymes

Used to cut strands of DNA at specific locations (restriction sites).

Polymerase chain reaction (PCR)

A technique that allows you to copy a piece of DNA without a cell.

Gel electrophoresis

A laboratory method that uses an electric current to separate DNA fragments based on their molecular size.

Gene cloning

Produces multiple identical copies of a gene.

Transformation

The process of inserting recombinant DNA into host cells.

Gene therapy

Inserting a normal gene (or editing an existing gene) to fix an absent or abnormal gene.

CRISPR

A gene editing technique that helps us to understand the genetics behind many diseases.

Stem cells

Undifferentiated cells that have the potential to become anything.

Selective breeding

Artificially breeding organisms with a desired trait.

Pharming

Producing pharmaceuticals in farm animals or plants.

GMO (Genetically modified organisms)

Organisms altered by recombinant DNA technology for desired traits.

Inbreeding

Crossing individuals that are closely related, which can cause health problems.

Hybridization

A type of selective breeding between unrelated organisms.

Characteristics of living organisms

Must be composed of one or more cells, contain DNA or RNA, capable of growth, reproduction, response to stimuli, adaptation, and have a metabolism.

Sexual reproduction

Involves 2 parents producing genetically unique offspring.

Asexual reproduction

Involves 1 parent producing genetically identical offspring.

Stimulus

A change in an organism's environment (cause).

Response

How an organism reacts to a change in its environment (effect).

Levels of ecological organization

Starting with the broadest to the most specific.

Biosphere

The zone and life on Earth, encompassing all of Earth's ecosystems.

Biome

Multiple ecosystems that share similar characteristics but are located in different parts of the planet.

Ecosystem

Community PLUS all of the abiotic factors in the environment.

Community

Multiple populations of different species living together.

Population

Multiple organisms of the same species living together.

Organism

Individual member of a species or population.

Ecology

The study of relationships between two organisms and between an organism and its environment.

Metabolism

All of the chemical reactions of each cell in an organism that provide energy for life's processes and create key molecules.

Biodiversity

The variety of organisms considered at all levels, from populations to ecosystems.