Biology AS Level Notes Summary

This set of flashcards covers key concepts in biology, particularly focused on classification, biodiversity, cellular processes, and the immune system.

What is classification in biology?

Classification is the process of dividing organisms into groups according to their similarities.

Why is classification important in biology?

It helps scientists identify unknown organisms, keep track of all organisms, communicate internationally, and study living organisms more easily.

Who introduced the binomial system of naming organisms?

Carolus Linnaeus, a Swedish botanist in the 1700s.

What does the binomial naming system consist of?

A two-word Latin name where the first part is the genus (capitalized) and the second part is the specific epithet (lowercase).

What is the hierarchical classification system?

A system that classifies organisms into a hierarchy of groups, starting from domain, kingdom, phylum, class, order, family, genus, to species.

What are homologous structures?

They are organs or skeletal elements that are similar in structure due to shared ancestry but may serve different functions.

What is natural classification based on?

It is based on evolutionary relationships and homologous features among organisms.

What is the purpose of dichotomous keys?

They help scientists identify living and non-living things using a series of choices that lead to the name of an item.

What is biodiversity?

The variety of life found in any habitat, including the diversity of species, ecosystems, and genetic variations.

Define ecosystem.

An ecosystem is a community of living organisms and their physical environment, including biotic and abiotic factors.

What is the biological species concept?

It defines a species as a group of populations whose members can interbreed in nature to produce viable, fertile offspring.

How does water pollution affect biodiversity?

Water pollution can lead to eutrophication and bioaccumulation, harming aquatic organisms and reducing biodiversity.

What is the significance of Simpson's Index of Diversity?

It measures biodiversity by considering both species richness and relative abundance, indicating the diversity of a given area.

How do vaccines work to prevent disease?

Vaccines contain antigens that stimulate an immune response, providing long-term immunity by generating memory cells.

Describe the structure and function of red blood cells.

Red blood cells are biconcave, flexible cells that contain hemoglobin for oxygen transport and lack a nucleus.

What is the primary function of enzymes?

Enzymes are biological catalysts that speed up chemical reactions without being consumed.

What are the two types of reversible enzyme inhibitors?

Competitive inhibitors, which bind to the active site, and non-competitive inhibitors, which bind to another site on the enzyme.

Describe the significance of telomeres.

Telomeres protect the ends of chromosomes during DNA replication, ensuring that genetic information is not lost.

What is the role of tRNA in protein synthesis?

tRNA transports specific amino acids to the ribosome and matches the anticodon with mRNA codons during translation.

How do mutations affect polypeptide synthesis?

Mutations can lead to changes in the amino acid sequence of proteins, potentially altering their function or causing diseases.

What is the importance of the Bohr effect?

The Bohr effect describes how increased carbon dioxide concentration decreases hemoglobin's affinity for oxygen, facilitating oxygen delivery to tissues.