HSC Biology Modules 5-8 Practice Flashcards

A comprehensive set of question-and-answer flashcards covering HSC Biology Modules 5 through 8, including reproduction, genetic variation, infectious and non-infectious diseases.

How is asexual reproduction defined in terms of offspring?

It requires only one organism to reproduce and form genetically identical offspring.

What condition must be met during cell division to ensure the continuity of a species?

The daughter cells should have the same type and number of genes as the parent cell, despite having genetic variation.

What are two advantages of external fertilisation recorded in the notes?

1. Requires no parental care, allowing the female to continue reproducing. 2. Greater genetic diversity as gametes from one organism can fertilise gametes from multiple others.

In plant reproduction, what is the 'radicle'?

The first root put out by the embryo for the absorption of water and nutrients during germination.

What is the function of 'receptacle' in a flower?

It is the swollen base of the flower which sometimes forms the succulent tissue of the fruit.

What is 'budding' as seen in fungi like yeast?

A type of asexual reproduction where a bud forms on the fungal cell and undergoes mitosis to make a complete DNA copy before breaking away.

What role does the hormone Progesterone play during pregnancy?

It ensures the thickness of the endometrium is maintained and suppresses uterine activity by inhibiting muscular contractions.

During the Follicular phase of menstruation, which hormone increases to stimulate follicle development?

Follicle stimulating hormone ($FSH$).

What occurs during the 'Acrosome reaction' in fertilisation?

The acrosome bursts and digests the zona pellucida, allowing the sperm to enter the egg.

Define the 'Sanger method' of DNA sequencing.

A process also called the chain termination method used to determine sections of DNA up to $900$ base pairs in length, utilised in the Human Genome Project.

In Mitosis, what happens during 'Anaphase'?

The spindle fibres pull the sister chromatids to opposite poles of the cell, where they are then termed daughter chromosomes.

What are the three components of a nucleotide?

A sugar molecule, a phosphate molecule, and a nitrogenous base bonded together.

According to the Watson and Crick model, how many hydrogen bonds connect Cytosine ($C$) and Guanine ($G$)?

$3$ hydrogen bonds.

Which enzyme is responsible for adding free-floating nucleotide bases in the $5' \rightarrow 3'$ direction during DNA replication?

DNA polymerase $$ III.

What is the 'central purpose' of polypeptide synthesis?

To create functional protein structures that enable an organism to fulfil various biological functions.

What is the difference between 'introns' and 'exons'?

Exons are coding regions of genes directly responsible for protein production, while introns are non-coding regions that are spliced out.

Which protein structure is defined by the sequence of amino acids held together by peptide bonds?

The Primary structure.

Define 'Aneuploidy' as a type of chromosomal mutation.

A condition where the number of chromosomes in offspring differs from the parent by one or multiple copies, such as in Down syndrome where there are $47$ chromosomes instead of $46$.

What is 'Gene Flow'?

Also called migration, it is the movement of genes from one population to another, serving as an important source of genetic variation.

What is the 'Founder effect' in genetic drift?

When a small number of individuals separate from a larger population to establish a new one, resulting in different allele frequencies and lower genetic variation.

What is a 'transgenic species'?

An organism whose genome has been deliberately altered by the transfer of a gene or genes from another species or breed.

Describe 'Somatic Cell Nuclear Transfer ($SCNT$)'.

A cloning method where the haploid nucleus of an egg is replaced with the diploid nucleus from a somatic cell, then stimulated to divide and implanted into a surrogate.

What are 'Prions'?

Non-cellular infectious proteins that are abnormally folded versions of normal proteins, usually affecting brain and neural tissue.

What is the mechanism of disease for a Virus?

It hijacks a host cell's enzymes and nutrients to make viral proteins and nucleic acids, which assemble into new viruses and are released to infect other cells.

What are Koch's Postulates?

A four-step procedure used to link a particular microorganism to a specific disease.

Which plant disease is caused by 'Fusarium Oxysporum' and affects Cavendish bananas?

Panama Disease.

Define 'Innate Immunity'.

The first and second lines of defence that are non-specific and react the same way to all entering pathogens, providing no immunological memory.

What is the role of 'B Memory' cells?

They remain in the body for many years to allow for a faster and stronger response if the same pathogen re-enters.

What is 'Herd Immunity'?

When a high proportion of a population is immunised, protecting the small number of unvaccinated people because there are not enough susceptible hosts for transmission.

How do 'Bacteriostatic' antibiotics function?

They stop bacteria from multiplying by interfering with DNA replication, protein production, or other metabolic processes.

What is the 'Miasma theory'?

An historical theory that diseases like cholera were caused by the smell of bad air or poisonous vapours from decaying matter.

What property does 'Conocurovone', found in the Western Australian smoke bush, possess?

The potential to destroy low concentrations of $HIV$.

Define 'Homeostasis'.

The maintenance of a stable or constant internal environment despite external and internal environmental changes.

Which hormone is released by 'Alpha cells' in the pancreas when blood glucose is low?

Glucagon.

What is 'Myopia'?

Short-sightedness where the image forms in front of the retina because the lens is too thick or the eyeball is too long.

How does 'Dialysis' assist in kidney failure?

It acts as an external machine (dialyser) that removes waste products and excess fluid from the blood, helping to maintain salt and water balance.