HSC Biology Module 5: Heredity Study Set

What is external fertilisation?

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

In Vitro Fertilisation (IVF)?

Differs from artificial insemination in that an egg is fertilised by a sperm outside the mother's body in an artificially created environment such as a Peri dish.

Where does external fertilisation usually occur?

In aquatic or moist terrestrial environments, to prevent the dehydration of gametes.

What is internal fertilisation?

Fertilisation that takes place inside the body of the female and involves mate attraction and copulation. As a result, fewer offspring are produced.

What effect does internal fertilisation have on an organism?

A significant energy investment and risk.

State the organisms in which external fertilisation occurs?

Most invertebrates and some vertebrates such as fish and amphibians.

State the organisms in which internal fertilisation occurs?

Most vertebrates such as reptiles, mammals and birds and some invertebrates such as insects and snails.

What are two advantages of external fertilisation?

-Results in the production of a large number of offspring.
-Easier to find mates as the gametes released can drift.

What are two advantages of internal fertilisation?

-More protection against outside environments and predators.
-Greater chance of successful fertilisation

Sexual reproduction?

Usually involves two parents who produce offspring that have a mix of the parents' genes and therefore differ from each other and from the parents.

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?

Is the process of creating new plants from a variety of sources: seeds, cuttings and other plant parts. Offspring are genetically identical to the parent.

Budding?

In reproduction 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. Spores are light and easily dispersed.

Binary Fission?

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

Which hormone is released to promote childbirth?

Oxytocin, promotes the contractions.

Placenta?

Provides oxygen and nutrients to the growing baby.

Follicle?

Is a fluid-filled sac that contains an immature egg, or oocyte. Releases oestrogen in the follicular phase of menstruation.

Follicular phase?

Days 1-14 of menstruation.

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.

Corpus luteum?

Is produced from the remnants of a burst follicle and produces oestrogen and progesterone.

Luteal phase?

Days 15-28 of menstruation.

Prostaglandin?

Plays a role in the ripening of the cervix. More or less prepares the cervix for the delivery of a baby.

Endocrine systems?

Chemical messaging systems consisting of hormones and the glands of the organism that carry those hormones directly into the circulatory system to be secreted to distant targeted organs.

Anther in plant reproduction?

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

Filament in plant reproduction?

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

Stigma in plant reproduction?

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

Style in plant reproduction?

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

Ovary in plant reproduction?

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

Artificial Insemination (AF)?

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

Artificial pollination?

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

Gymnosperms?

Seed bearing vascular plants, such as cycads, in which the ovules or seeds of the plant are not enclosed in an ovary but exposed.

Angiosperms?

Are vascular plants. Angiosperms ovules or 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. For dioecious plants to reproduce, a male plant must be near a female plant so that pollinators can do their work.

Bryophytes?

Play a vital role in regulating ecosystems. Other systems benefit from the water and nutrients that bryophytes collect.

Mitosis interphase?

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

Mitosis prophase?

Chromosomes condense, become visible and spindle apparatus forms.

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?

A thread-like structure of nucleic acids (DNA or RNA) and protein found in the nucleus of most living cells, carrying genetic information in the form of genes.

Gametes?

Sex cells.

Centromere?

The point where the two chromosomes join

Homologous chromosomes?

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

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?

Chromosomes separate into homologous pairs.

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?

-Daughter chromosomes move apart, to opposite poles.

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.

What are the four nitrogenous bases?

Adenine, Thymine, Guanine, Cytosine.

RNA?

Single-stranded molecule made of nucleotides, with a ribose sugar attached to each phosphate to form the backbone; on the other end it attaches to a base, either A, uracil (U), C or G.

Purine base?

Nitrogenous bases adenine and guanine.

Pyrimidine base?

Nitrogenous bases thymine and cytosine.

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?

Often referred to as the building blocks of proteins, are compounds that play many critical roles in your body. Is a chemical building block of polypeptides.

Polypeptides?

Are chains of amino acids. Proteins are made up of one or more polypeptide molecules. Peptide bonds hold the amino acids together.

Protein?

A large molecule made up of polypeptides chains, formed by sequences of amino acids linked together by peptide bonds and which contain other chemical elements

DNA?

Consists of long chains of nucleotides wound into a double helix. The sequence of nucleotide bases determines the meaning of the message.

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.

Locus (Pl. Loci)?

A segment of DNA; the position of a gene on a chromosome.

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.

Epigenetic?

Chemical modifications of DNA that do not involve a change in the sequence of nucleotides. Usually environmental.