Life Sciences 11 Vocabulary

Flashcards covering key vocabulary from Life Sciences 11 lecture notes.

Cell Theory

States that all living organisms are made of cells, the cell is the basic unit of life, and all cells come from pre-existing cells.

Cell

The smallest unit of life that performs functions necessary for living organisms.

Prokaryotic Cells

Simpler cells without a nucleus or membrane-bound organelles. Example: Bacteria and Archaea

Eukaryotic Cells

Complex cells containing a true nucleus and specialized organelles. Example: plants, animals, fungi, and protists.

Cell Membrane

Semi-permeable phospholipid bilayer that controls substance exchange and maintains homeostasis.

Cytoplasm

Gel-like substance that fills the cell and contains enzymes, organelles, and the cytoskeleton.

Nucleus

Contains genetic material (DNA) and controls all cellular activities, including growth and reproduction.

Mitochondria

The powerhouse of the cell; converts glucose into ATP through aerobic cellular respiration.

Ribosomes

Made of RNA and proteins; site of protein synthesis, can be free-floating or attached to ER.

Endoplasmic Reticulum (ER)

Rough ER: Studded with ribosomes, involved in protein production and transport. Smooth ER: Synthesizes lipids, detoxifies drugs/poisons, stores calcium ions.

Golgi Apparatus

Modifies, sorts, and packages proteins and lipids into vesicles for secretion or use in the cell.

Lysosomes

Contain digestive enzymes to break down waste, old organelles, and pathogens.

Vacuole

Stores water, nutrients, and waste; large central vacuole in plant cells helps maintain turgor pressure.

Chloroplasts

Site of photosynthesis in plant cells; convert sunlight, carbon dioxide, and water into glucose and oxygen.

Cell Wall

Provides structural support and protection in plants, fungi, and bacteria; made of cellulose in plants.

Pathogens

Agents that cause disease or illness to their hosts.

Viruses

Non-cellular pathogens consisting of genetic material (DNA or RNA) surrounded by a protein coat; reproduce only by infecting host cells.

Bacteria

Single-celled prokaryotes; some are harmful (pathogenic), while others are beneficial.

Protists

Eukaryotic microorganisms; some are parasitic and cause diseases.

Fungi

Can be single-celled (yeasts) or multicellular (molds); some cause infections.

Prions

Misfolded proteins that cause neurodegenerative diseases; no DNA/RNA.

Direct Contact

Physical touch, bodily fluids, open wounds, or contact with contaminated surfaces.

Fomites

Inanimate objects (e.g., doorknobs, towels) that can carry infectious agents.

Airborne Transmission

Pathogens carried in droplets from coughing or sneezing.

Animal Vectors

Mosquitoes, ticks, and fleas can carry and transmit pathogens.

First Line of Defense

Includes skin, mucous membranes, stomach acid, tears, and saliva.

Second Line of Defense

Includes inflammation, fever, phagocytes, and NK cells.

Third Line of Defense

Specific, adaptive immune response involving T-cells, B-cells, and memory cells.

Vaccines

Contain weakened, inactivated, or fragments of pathogens that stimulate the immune system.

Antibiotics

Medications that kill or inhibit the growth of bacteria.

Antivirals

Drugs designed to slow down or stop the replication of viruses within host cells.

Public Health Measures

Non-medical methods that help reduce the spread of infectious diseases, e.g., hand washing, PPE, quarantine.

Herd Immunity

High percentage of a population becomes immune, making it difficult for a disease to spread.

Lytic Cycle

Viral DNA hijacks the host cell to produce new viruses, eventually lysing the cell to release them.

Lysogenic Cycle

Viral DNA integrates into the host genome and remains dormant before entering the lytic cycle.

Evolution

The process through which species change and adapt over long periods of time.

Natural Selection

The process where organisms with advantageous traits are more likely to reproduce.

Mutation

Random changes in genetic material, which can introduce new traits into a population.

Gene Flow

Occurs when individuals from different populations interbreed, introducing new genetic material.

Genetic Drift

Random changes in allele frequencies within a population, especially in small populations.

Speciation

The process by which one species splits into two or more separate species over time.

Allopatric Speciation

Occurs when a physical barrier divides a population into two.

Sympatric Speciation

A new species evolves from a single population without physical barriers.

Adaptation

The process through which species develop traits that help them survive and reproduce in their environment.

Ecology

The scientific study of how organisms interact with each other and their environment.

Biotic Factors

The living parts of an ecosystem, such as plants, animals, fungi, and bacteria.

Abiotic Factors

Non-living things like sunlight, temperature, water, soil, and air.

Carrying Capacity

The maximum number of individuals an environment can support.

Taxonomy

Science of naming and classifying organisms based on shared characteristics.

Binomial Naming

Every species has a unique scientific name that consists of two parts – its genus and species names.