Biology 1020 Unit 2 Glossary Terms

Concentration Gradient

The difference is solute concentration between two solutions

Diffusion

The movement of molecules from areas of high concentration to areas of lower concentration; typically used with reference to solute

Hypertonic

Descriptive of a solution that contains more solute particles than a second solution; a hypertonic solution has a lower water potential than a hypotonic solution

Hypotonic

Descriptive of a solution that contains fewer solute particles than a second solution; a hypotonic solution has a higher water potential than a hypertonic solution.

Isotonic

Descriptive of a solution that contains the same amount of solute particles as another solution

Osmosis

The special case of diffusion involving the movement of water molecules (solvent)

Selective Permeability

A characteristic of a membrane that permits certain materials to move through it while others are resisted

Solute

The dissolved particles in a solution

Solvent

In a solution, the most abundant molecule; for biological systems, the solvent is water

Turgor Pressure

Water pressure in a plant cell; acts in opposition to water potential

Water Potential

The potential energy of a volume of water, expressed as a pressure

Activation Energy

energy required to cause a chemical reaction to proceed

Active Site

Position on an enzyme molecule where substrate molecules come together to form a chemical reaction

Amino Acid

Organic compound that is used as the “building block” of proteins

Catalyst

A substance that promotes a chemical reaction, but is not consumed in that reaction

Cofactor

A mineral ion or organic molecule that is required by an enzyme in order to achieve its catalytic effect

Denaturation

Disruption of the 3-dimensional shape of an enzyme molecule

Enzyme

A biological catalyst; virtually all enzymes are proteins

Optimum

The most favorable condition

pH

A measure of concentration of protons (positively-charged particles, or H+) in a solution

Primary Structure

A sequence of amino acids in a polypeptide chain

Products

The molecules that are made in a chemical reaction

Protein

Large molecules composed of sub-units called amino acids that are linked by peptide bonds; often referred to as polypeptides

Quaternary Structure

Structure of a protein that is composed of 2 or more chains of amino acids (i.e., 2 or more polypeptides)

Rate

Amount of activity of a biological process per unit time

Secondary Structure

The folding or twisting of a polypeptide chain along its long axis

Substrate

The molecules that are acted upon by an enzyme

Tertiary Structure

The bending and folding of a polypeptide after it has assumed its secondary structure

Alveoli

Tiny thin-walled air sacs at the ends of the bronchioles in the lungs, surrounded by capillaries

Bronchi

Tubes branching from the trachea that carry air into each lung

Bronchioles

Tubes from the bronchi that lead to clusters of the alveoli

Diaphragm

Large muscles at the floor of the chest cavity; contraction of this muscle expands the chest cavity and draws air into the lungs

Ectotherm

Organism whose body temperature is determined primarily by the temperature of their environment

Embryo

Developing organism; “baby” plant or animal

Endosperm

Food source for developing plant embryo

Endotherm

Organism whose body temperature is maintained independently of environmental temperature, usually at a metabolically optimal level

Epiglottis

Flap at the top of the trachea that prevents food from entering or blocking the pathway of air into the lungs

Metabolism

The collection of chemical reactions that occur in organisms

Spiracle

Opening in insect body wall through which air enters tracheae

Thermal Strategy

Metabolic patterns of organisms

Trachea

Air tube leading from the back of the mouth down into the chest cavity; the “windpipe”

Tracheae

Tiny tubes in insect body that deliver oxygen directly to metabolizing cells and tissues

Anaphase

The phase of cell division during which chromatids or homologous chromosomes separate and move to opposite ends of the cell

Asexual Reproduction

Reproduction not involving the fusion of gametes

Cell Plate

Partition that forms during cytokinesis in plant cells to produce separate daughter cells

Centromere

Structure in a chromosome that joins replicated chromatids; spindle fibers attach here

Chromatid

One of the 2 replicas pf a duplicated chromosome (both of which are joined by a single centromere)

Chromosome

The structure in a nucleus that contains genetic information

Cleavage Furrow

Constriction that forms around the middle of animal cells during cytokinesis to subdivide cytoplasm

Cytokinesis

Division of the cytoplasm following mitosis of meiosis

Daughter Cells

The products of cell division following cytokinesis

Diploid

Condition in which a cell or organism has 2 sets of chromosomes (one set from each parent)

Gametes

Mature sex cells (eggs and sperm); the haploid products of meiosis

Haploid

Condition in which a cell or organism has one set of chromosomes; typical of gametes

Homologous Chromosomes

Physically similar chromosomes that pair up during synapsis; one homologous chromosome is inherited from the mother while the other from inherited from the father

Karyotype

A picture of the chromosome complement of a cell

Meiosis

Nuclear division in which the number of chromosomes is reduced by one-half; homologous chromosomes are separated from one another

Metaphase

The phase of cell division where the chromosomal material is lined up in the center of the cell

Mitosis

Nuclear division that produces daughter cells that are identical to the original cell

Oogenesis

Meiosis that produces egg cells

Prophase

The phase of cell division during which the nuclear membrane disappears and the chromosomes become visible

Sexual Reproduction

Reproduction involving the fusion of haploid gametes from two different parents to produce a diploid zygote

Spermatogenesis

Meiosis that produces sperm

Spindle Fibers

Microtubules that attach to the centromere and move the chromosome around the cytoplasm during cell division

Synapsis

Pairing of replicated homologous chromosomes during meiosis

Telophase

The phase of cell division during which the nuclear membrane reappears and the chromosomes disappear

Zygote

A diploid cell formed by the fusion of 2 haploid gametes

Is a tomato plant a haploid or diploid organism?

Diploid

If an organism has 24 chromosomes (2n=24), how many chromosomes will each daughter cell have after mitosis?

24

If an organism has 24 chromosomes (2n=24), how many chromosomes will each daughter cell have after meiosis?

12 (hint - this process produces haploid cells [n - half of the diploid number])

A tomato plant has 24 chromosomes in its body (somatic) cells. When it produces pollen and ovules, are these gametes…

haploid

If a carrot is placed in two separate solutions and one is hypotonic, will the carrot be flaccid (soft) or turgid (firm)?

Turgid (Firm)

What happens when cells are placed in a isotonic solution?

The cells remain the same - do not shrink or inflate

What happens when cells are placed in a hypertonic solution?

They shrink

What happens when cells are placed in a hypotonic solution?

They expand