Biology Unit 2: Cells, Development, Biodiversity and Conservation Flashcards

This set of vocabulary flashcards covers key concepts from the Biology UNIT 2 exam, including cellular processes, plant anatomy, genetic diversity, and historical drug testing methods.

Telophase (Plant Cell)

A stage of mitosis in plant cells where the cell plate forms and nuclear envelopes reform around the divided sets of chromosomes.

Safranin

A slide stain used in light microscopy to identify lignin and nucleic acids, helpful for observing cells in mitosis.

Mitotic Index

A ratio determined by dividing the number of cells undergoing mitosis (prophase, metaphase, anaphase, telophase) by the total number of cells in the population.

Amyloplast

A specialized part of a plant cell used for the storage of starch.

Lysosome

An animal cell organelle with a diameter of approximately $0.2\,\mu m$ that functions to digest cellular materials.

Index of Diversity ($D$)

A measure of biodiversity calculated using the formula $D = \frac{N(N-1)}{\sum{n(n-1)}}$, where $N$ is the total number of individuals of all species and $n$ is the total number of individuals of each species.

Tiger Subspecies

Variations of the tiger species classified into groups such as Bengal, Indo-Chinese, and the extinct Caspian tiger.

Jute Fibres

Plant tissues with high tensile strength that are renewable and used to make sustainable products like bags and string.

Antimicrobial Inhibition Zone

The area on an agar plate where bacteria cannot grow due to the presence of an extract, such as those from jute leaves or seeds.

William Withering

An 18th-century scientist who developed a drug testing method for foxglove extract to treat heart conditions by amending dosage based on patient response.

Cryopreservation

An alternative storage method for endangered plant species involving the placement of embryo tissue into liquid nitrogen at $-196^{\circ}C$.

Embryo (Fertilisation)

The structure produced when a male nucleus fuses with an egg cell nucleus during fertilisation.

Cortical Granules

Organelles in egg cells that are transported to the cell surface membrane by protein fibres to prevent multiple sperm from entering.

Rab27a

The gene that contains the genetic information for the production of protein fibres responsible for transporting cortical granules to the cell surface.

Gene Duplication

An occurrence resulting from errors in DNA replication and crossing over that produces additional copies of a gene, such as the amylase gene $AMY1$.

Crossing Over

A process occurring in the early stages of meiosis where homologous chromosomes exchange genetic material.

Maltase

An extracellular enzyme produced in the small intestine that breaks down maltose into $\alpha\text{-glucose}$ for use in respiration.