HSC Biology Module 5: Heredity DEFINITIONS

External fertilisation.

Fertilisation where a male organism's sperm fertilising a female organism's egg outside of the female's body.

Internal fertilisation.

Fertilisation that takes place inside the body of the female and involves mate attraction and copulation.

Sexual reproduction.

Usually involves two parents who produce offspring that have a mix of the parents' genes.

Asexual reproduction.

Involves only one parent and gives rise to offspring that are genetically identical to each other and to the original parent.

Vegetative propagation.

The process of creating new plants from a variety of sources: seeds, cuttings and other plant parts.

Budding.

An adult organism gives rise to a small bud, which separates from the parent and grows into a new identical individual. Also occurs in protists.

Spores.

Tiny, unicellular reproductive cells that are produced in great numbers by organisms such as fungi and some plants.

Binary Fission.

Splitting into two where a newly divided cell grows to twice its size, replicates its genetic material (DNA) and then splits into two identical cells.

Childbirth hormone.

Oxytocin, promotes the contractions.

Placenta.

Provides oxygen and nutrients to the growing baby.

Oestrogen.

Is a hormone released during both the follicular and luteal phases of menstruation that thickens the uterus lining.

Progesterone.

Is a hormone released during the luteal phase of menstruation that stabilizes the uterus lining.

Plant anther.

Male part of the plant and is where pollen grains are formed.

Plant filament.

Male part of the plant and is the stalk that carries the anther.

Plant stigma.

Female part of the plant and is the sticky top surface of the flower, to which pollen adheres.

Plant style.

Female part of the plant that joins the stigma to the ovary.

Plant ovary.

Female part of the plant and is where the ovules are formed.

Artificial Insemination (AF).

Collecting sperm from a chosen male and artificially introducing it into several selected females.

In Vitro Fertilisation (IVF).

An egg is fertilised by a sperm outside the mother's body.

Artificial pollination.

Involves removing the stamens of a flower and dusting the pollen onto the stigma of the same flower or another flower.

Gymnosperms.

Seeds of the plant are not enclosed in an ovary but exposed.

Angiosperms.

Seeds are found in the flower. Examples include mangos.

Monoecious plants.

Are plants that have male and female flowers on the same plant.

Dioecious plants.

Plants that have either male or female flowers but not both.

Mitosis interphase.

DNA replication complete. Chromosomes replicate to become double-stranded.

Mitosis prophase.

DNA replication compete.

Chromosomes split down the middle to form the X.

Mitosis metaphase.

Double-stranded chromosomes align along the equator of the cell.

Mitosis anaphase.

Sister chromatids (single chromosomes) separate to opposite poles of cell.

Mitosis telophase.

Nuclear membranes assemble around the two nuclei. Each nuclei with the same number of chromosomes as the parent cell. Diploid.

Mitosis cytokinesis.

Division of cytoplasm into two cells.

Mitosis.

Leads to the formation of two identical daughter cells that contribute to the growth and repair of the organism.

Chromosome.

Found in the nucleus of most living cells, carrying genetic information in the form of genes.

Homologous chromosomes.

Are the same length, have the centromere in the same position and carry genes for particular characteristics at the same loci.

Diploid number.

Cell condition in which two of each type of chromosome are present. Number: 46

Haploid number.

Cell condition in which only one of each type of chromosome is present. Number: 23

Meiosis.

Gives rise to gametes that transmit genetic material from one generation to the next during sexual reproduction.

Meiosis early prophase.

DNA strand replication is complete.

Meiosis late prophase.

-Nuclear membrane breaks down.

-Chromosomes split into chromatids.

-Crossing over occurs: genetic variation occurs.

Meiosis metaphase 1.

-Chromosomes align in pairs in the middle of the cell.

-Random segregation

Meiosis anaphase I.

-Chromosome pairs separate and each chromosome moves to the opposite end of the cell.

Meiosis telophase.

-Two daughter cells form.

-Chromosome number is halved.

-Chromosome combinations in cells differ.

Meiosis cytokinesis 1.

-Daughter cells are not identical to each other and have half the original number of chromosomes.

Meiosis metaphase II.

-Chromosomes align at the equator.

Meiosis anaphase II.

-Chromatids are pulled apart, to opposite poles.

-Now four potencial cells with 23 single stranded chromosomes.

Meiosis cytokinesis II.

-Four resulting daughter cells are not genetically identical to each other and have half the original chromosome number.

Nucleotide.

Consists of three parts - a phosphate, a sugar and a nitrogenous base.

RNA.

Single-stranded molecule made of nucleotides, with a ribose sugar attached to each phosphate. Half a helix.

Eukaryote.

Cells that have a membrane-bound nucleus and membrane-bound organelles. Examples include: animals and plants.

Prokaryotic.

Cells that exist as single cells and have no membrane nucleus or organelles. Examples include: bacteria and archaea kingdom.

Eukaryotic DNA.

-Nuclear DNA

-Some non-nuclear DNA (mitochondrial)

-Many chromosomes

-Contains non-coding DNA

-DNA is packaged in linear form

Prokaryotic DNA.

-Non-nuclear DNA

-Circular (looped DNA)

-Contains non-chromosomes DNA called plasmids

-Contains 1 circular chromosomal DNA.

Amino acid.

The building blocks of proteins. Is a chemical building block of polypeptides.

Polypeptides.

Are chains of amino acids. Proteins are made up of one or more polypeptide molecules.

Protein.

A large molecule made up of polypeptides chains, formed by sequences of amino acids.

DNA.

Consists of long chains of nucleotides wound into a double helix.

Messenger RNA (mRNA).

Is a copy of one side of an unzipped DNA double helix except the nucleotide Thymine is replaced with Uracil. Plays an important role in the production of proteins.

Transfer RNA (tRNA).

An RNA molecule that functions as an interpreter picking up specific amino acids and recognising the appropriate codons to attach to on the mRNA.

Gene.

A segment of DNA on a chromosome that codes for a specific trait.

Genome.

The complete set of genetic material within a cell or that an organism has in each of its cells.

Alleles.

Are different forms of the same gene.

Trait.

A particular physical feature or characteristic of an organism.

Phenotype.

Includes the structure, behaviour and physiology of an organism.

Fibrous proteins.

Forms structural components of cells and tissues.

Globular proteins.

Usually spherical in shape and are often transport proteins, such as hemoglobin in the blood.

Structural proteins.

Are often fibrous and stringy and found in connective tissues such as skin, cartilage, bone, tendons and ligaments. Collagen

Enzymes.

Are protein molecules involved in all biochemical aspects of cellular metabolism.

Transport and storage proteins.

Proteins that bind to carry or store chemicals in the body.

Sensory proteins.

Some proteins change their shape or biochemical activity in response to stimuli.

Dominant allele.

In hybrid individuals (heterozygous individuals e.g. Tt), the trait that is expressed (appears).

Recessive allele.

An allele that is masked when a dominant allele is present. E.g small t in allele Tt.

Co-dominant.

Some alleles are equally dominant and neither are masked by the other. When both alleles are present, they are both expressed in the phenotype. E.g spotty coloured cows.

Incomplete dominance.

One allele does not completely dominate another allele, and therefore results in a new phenotype. E.g. red and white flowers producing pink flowers.

Aa allele.

Heterozygous.

AA allele.

Homozygous dominant.

aa allele.

Homozygous recessive.

Genotype.

The genetic makeup of an organism determining its physical appearance or phenotype.

Monohybrid.

Are heterogenous (Tt) and with respect to only one feature. E.g. Red or White.

Dihybrid.

Are heterogenous (Tt) with respect to two features. E.g. Red or White and Tall or Short.

Trihybrid.

Are heterogenous (Tt) with respect to three features. E.g. Red or White and Tall or Short and Wrinkled or Not Wrinkled.

Sex-linkage.

Refers to the pattern of inheritance being different in that of males and females.

Multiple alleles.

Is the inheritance of a characteristic in which there are more than two forms of alleles. E.g. Blood types.

Phenotypic frequencies.

Is defined as the number of individuals that exhibit the designated phenotypes.

Genotypic frequencies.

Is the number of individuals with a given genotype divided by the total number of individuals in the population.

Allele frequencies.

Is a measure of how common an allele is in a population.

SNP.

Is a single incorrectly inserted nucleotide in the non-coding region, creating an error in the DNA sequence. Must occur in at least 1% of the population.

SNP uses.

Important genetic markers used to distinguish individuals and identify disease susceptibility.

DNA sequencing.

The process used to determine the order of nucleotides in DNA.

Technologies used in DNA sequencing.

-PCR.

-The Sanger method.

DNA Profiling.

Used to determine an individual's DNA characteristics, often for the purposes of paternity testing, identification or remains or criminal investigations.

What processes are used in DNA profiling.

-Short tandem repeats.

-PCR.

-Gel Electrophoresis.

STRs (short tandem repeats).

Sections of non-coding DNA that are repeated many times over (for example: TATATATATA).

The polymerase chain reaction (PCR).

Involves taking a piece of DNA and increasing its copies so as to aid in the process of DNA profiling.

Gel electrophoresis.

Used to separate the segments under study according to length and molecular weight.

Population genetics.

Investigates factors that influence the change of frequency of alleles over time and across locations and populations.

Genetic diversity.

Important for the survival of endangered species or isolated populations.

Tasmanian devil genetic diversity example.

Are at risk from a contagious cancer (DFTD) that is linked to the low diversity of genes associated with its immune system.

Genome-wide associations (GWA).

Helped to collect and analyse data on the genetic components of disease.

mtDNA and human evolution.

Is used a molecular clock to determine the date of the last common ancestor.

Nuclear DNA and mtDNA uses.

To compare modern humans with recent ancestors such as Neanderthals.

Study to determine the inheritance of disease or disorder.

The frequency of sickle-cell anaemia (SNP affecting the transportation of haemoglobin) is higher in areas exposed to malaria. Provides resistance to the protozoan pathogen.