IB Biology Topic 2 Definitions

The process of taking substances into cells and blood

Not consisting of, divided into, or containing cells

An enzyme-filled sac in sperm cells responsible for digesting the outer layer of the egg cell

The depolarization, repolarization, and hyperpolarization of a neuron

The movement of substances across membranes usually against concentration gradients, requiring energy from ATP

A molecule's property of being both hydrophobic and hydrophilic

Small mutations that accumulate over time in a virus's surface antigens, leading to immune system evasion

The process by which two or more different viruses or different strains infect the same cell and create a novel subtype

An active transport protein that transports two molecules in opposite directions

The homologous pairs of chromosomes that do not determine sex

A reproductive method where all internal structures are copied and split equally into two identical daughter cells

Cancer-causing mutagens

The location of crossing over that is completely random

Organelles in plant cells where light-dependent reactions of photosynthesis occur

A synapse that uses acetylcholine as a neurotransmitter

A protein that forms a lattice around newly forming vesicles, playing an important role in vesicle formation

Folds of the inner membrane in mitochondria, increasing the surface area for oxidative phosphorylation

The exchange of DNA sequences of non-sister chromatids of homologous chromosomes

A protein that is involved in control of the cell cycle

A large group of peptides and small proteins that coordinate immune responses over short and long distances, including interferons (IFs), interleukins (ILs), and tumor necrosis factors (TNFs)

Post-mitosis, a contractile ring of protein contracts to pull the plasma membrane inward, splitting the cell into two genetically identical daugther cells

Structures that fuse cardiac cells together to provide structural integrity

The growth and development of cells into specialized cell types

The net passive movement of particles from areas of high concentration to areas of low concentration, requiring no energy

A cell that contains both chromosomes in a homologous pair

The collective properties that develop in a group of cells that each individual cell cannot carry out

Invagination of the plasma membrane around substances to form a vesicle that transports substances into the cell

The absorbance of a smaller cell by a larger cell with a vesicle so that the smaller cell now performs functions for the larger cell

The study of epigenomes

A person's pattern of gene expression

Red blood cells that have a flattened disc shape with invaginations to increase surface area for oxygen diffusion and binding to haemoglobin

The theory that viruses evolved from genetic material released from the genes and encapsulated in the proteins of larger organisms

A multicellular organism with complex cell structure and compartmentalization

Release of substances into the extra-cellular matrix through fusion of vesicles with the plasma membrane

The passive movement of particles from areas of high concentration to areas of low concentration via specific channel proteins

A state where the plant cell has lost water and turgor pressure, causing it to become limp

Sex cell

The conversion of genes to proteins to express the gene's coded characteristic

All the genes in an organism

Stacks of thylakoids that optimize light absorption and are distributed throughout the stroma

A cell that contains one chromosome of the homologous pair

A infection that is notoriously difficult to treat beause it infects lymphocytes involved in antibody production and can destroy them over time, preventing antibody production

Paired chromosomes with the same gene sequence but potentially different alleles

Attracted to water (water-loving)

Repelled to water (water-fearing)

The pressure exerted by a fluid in a closed system, affecting water potential

A solution with a higher solute concentration than another solution

A solution with a lower solute concentration than another solution

Lacking the ability to move or function independently

A protein embedded in the plasma membrane

The cell's active period wherein it grows, lives, and prepares for mitosis

A solution with the same solute concentration as another solution

Neutral molecule or anion with a non-bonding pair of electrons (commonly water)

The process by which light is absorbed by an organism for use in cellular processes

Microscopy that uses light to view objects and has a low resolution

A viral replication cycle where the viral DNA integrates into the host cell's genome, replicates along with the host cell, and can eventually switch to the lytic cycle

A viral replication cycle where the virus attaches to the host cell, injects its genome, replicates using the host's machinery, assembles new viruses, and kills the host cell to release the new viruses

The cytoplasm of the mitochondria, containing enzymes for the link reaction and Krebs cycle

The process by which one diploid nucleus divides to form four haploid nuclei

The sum of all chemical reactions taking place within an organism

A process where primary tumor cells detach and travel to another body site via the bloodstream

The addition of methyl groups to DNA to prevent transcription

Hair-like structures that increase the surface area of a cell for absorption and diffusion

Organelles in cells where the link reaction, Krebs cycle, and oxidative phosphorylation occur, producing ATP

The division of the nucleus into two genetically identical daughter nuclei

The ratio of the number of cells undergoing mitosis to the total number of visible cells

A substance capable of causing a mutation

A random change to the base sequence of a gene

Long contractile fibers within a muscle cell

The process whereby substances decrease each other's levels

A nervous system cell that carries electrical impulses from the brain to the body or vice versa

Chemical messengers released in synapses to carry signals to another neuron, gland, or muscle cell

The improper detachment of chromosomes during anaphase I or II

The organelle in eukaryotic cells that contains genetic material, controls the cell, and is bounded by a double nuclear membrane

Genes involved in regulation of the cell cycle

The movement of water from a region of low solute concentration to a region of high solute concentration, across a partially permeable cell membrane

An organism or virus that causes a disease

A protein on the surface of the plasma membrane

A single chromosome of naked circular DNA found in prokaryotes

The process in which cells lose water in a hypertonic solution, causing the cell membrane to pull away from the cell wall and leaving the cell flaccid

An ability of a cell to develop into many specialized cell types

The process whereby substances increase each other's levels

The process of splicing exons and removing introns from an mRNA strand after transcription to form mature mRNA for translation

A unicellular organism with simple cell structure and no compartmentalization

The random lining up of homologous pairs at the equator during metaphase I

The theory that viruses were once small cells that were parasites in larger cells and over time lost the genes not required, becoming fully dependent on host cells

The ability of a microscope to distinguish two objects

The replication process of retroviruses, like HIV, which reverse transcribe their RNA into DNA to integrate into the host genome

Organelles responsible for protein synthesis, found free within the cytoplasm and associated with the endoplasmic reticulum

The process of a signal jumping from node to node

The plasma membrane of a muscle fiber

A network of tubules in muscle fibers that stores calcium ions and coordinates muscle contraction

Microscopy that uses an electron beam to view the surface of an object

The homologous pair of chromosomes that determines sex

The passive movement of particles from areas of high concentration to areas of low concentration across a semi-permeable membrane

A pluripotent cell that is necessary in embryonic development, growth, and cell renewal

The chloroplast cytoplasm containing starch grains, lipid droplets, and enzymes for the light-independent reactions

A substance secreted by Type II pneumocytes that reduces surface tension in the alveoli, preventing collapse and aiding in gas exchange

The living together of two organisms

The junction between two neurons or between a neuron and receptor or effector cell

The tight pairing up of homologous chromosomes

The space between two neurons or between a neuron and receptor or effector cell

Internal membrane systems in chloroplasts that increase surface area for light-dependent reactions

An embryonic stem cell that can develop into any cell type.

Microscopy that uses an electron to beam to view very small and thin slices and has a high resolution

An individual that has three homologous chromosomes instead of a pair

The pressure exerted by water inside the cell against the cell wall, contributing to the plant cell's rigidity

Small membrane-bound sacs formed during exocytosis or endocytosis, transporting substances within and out of the cell

The theory that viruses evolved at the same time as the first cells and have been dependent on them since the beginning

A channel whose state is dependent on the axon charge

A gelatinous layer around the egg cell that prevents sperm entry before and after fertilization