Biology 8 Comps

Hypotonic Solution

A solution in which the concentration of solutes is less than that inside the cell.

Enzyme Active Site

The specific region of an enzyme where substrate molecules bind and undergo a chemical reaction, characterized by a shape complementary to the substrate.

Enzyme-Substrate Complex

A complex formed when a substrate binds to the active site of an enzyme, which facilitates the chemical reaction by lowering activation energy.

Optimal pH for Enzymes

The pH at which an enzyme functions most efficiently; deviations can denature the enzyme and reduce its activity by altering its structure.

Enzyme Denaturation

The loss of an enzyme's three-dimensional structure and function, often caused by high temperatures or extreme pH levels, disrupting its active site.

Competitive Enzyme Inhibitors

Inhibitors that bind to the active site of an enzyme, directly preventing substrate binding and thus inhibiting enzyme activity.

Non-Competitive Enzyme Inhibitors

Inhibitors that bind to a site on the enzyme other than the active site, causing a conformational change that reduces its ability to bind substrates.

Allosteric Regulation

The regulation of an enzyme by binding an effector molecule at a site other than the enzyme's active site, either activating or inhibiting the enzyme.

Phospholipid Structure

Composed of a glycerol molecule, two fatty acids (hydrophobic), and a phosphate group (hydrophilic), forming the basic structure of cell membranes.

Amphipathic Nature of Phospholipids

Phospholipids have both hydrophilic (phosphate group) and hydrophobic (fatty acid tails) regions, allowing them to form bilayers in aqueous environments.

Selective Permeability

The property of a plasma membrane that allows some substances to cross more easily than others, crucial for maintaining cell homeostasis.

Concentration Gradient

The difference in concentration of a substance across a space, driving passive transport processes like diffusion.

Tonicity

The ability of a surrounding solution to cause a cell to gain or lose water, affecting cell volume and function.

Isotonic Solution

A solution with the same solute concentration as inside the cell, resulting in no net water movement across the cell membrane.

Hypotonic Solution

A solution in which the solute concentration is less than inside the cell, causing water to move into the cell, potentially leading to lysis.

Hypertonic Solution

A solution in which the solute concentration is greater than inside the cell, causing water to move out of the cell, leading to crenation or shrinkage.

Exocytosis

The process by which cells expel substances into the extracellular space via vesicles fusing with the plasma membrane.

Phagocytosis

A type of endocytosis in which a cell engulfs large particles or whole cells, important in immune responses and nutrient acquisition.

Pinocytosis

A type of endocytosis in which the cell ingests extracellular fluid and its dissolved solutes, sampling the cell's environment.

Allele

A specific version of a gene at a given locus on a chromosome, contributing to genetic variation.

Genetic Drift

A change in the allele frequency of a population due to random chance events, significant in small populations.

Prokaryotic Cells

Cells lacking a nucleus or other membrane-bound organelles; includes bacteria and archaea, characterized by simple internal organization.

Eukaryotic Cells

Cells containing a nucleus and other membrane-bound organelles, allowing for compartmentalization and complex functions; includes animal, plant, fungi, and protist cells.

Dominant Allele

An allele that expresses its phenotype even when paired with a recessive allele in a heterozygous individual; masks the effect of the recessive allele.

Recessive Allele

An allele that only expresses its phenotype when present in a homozygous condition; masked by a dominant allele in heterozygotes.

Nucleotides

The building blocks of DNA and RNA, consisting of a deoxyribose or ribose sugar, a phosphate group, and a nitrogenous base.

DNA Nitrogenous Bases

Adenine (A), guanine (G), cytosine (C), and thymine (T) are the four nitrogenous bases in DNA, encoding genetic information.

Base Pairing Rules

In DNA, adenine (A) pairs with thymine (T), and guanine (G) pairs with cytosine (C), forming the double helix structure.

DNA Polymerase

The primary enzyme involved in DNA replication, adding nucleotides to the growing DNA strand using a template.

Transcription

The process of creating an RNA copy from a DNA template, initiating gene expression.

RNA Polymerase

The enzyme that synthesizes RNA from a DNA template during transcription, critical for gene expression.

Translation

The process of decoding mRNA to synthesize a protein on ribosomes, translating genetic information into functional molecules.

Codon

A sequence of three nucleotides that codes for a specific amino acid or a stop signal during translation.

mRNA (messenger RNA)

An RNA molecule that carries genetic information from DNA to the ribosome for protein synthesis, directing the sequence of amino acids.

tRNA (transfer RNA)

An RNA molecule that carries amino acids to the ribosome, matching them to the mRNA codon to build a protein.

Ribosome

A cellular structure composed of RNA and protein, where protein synthesis occurs by translating mRNA codons into amino acid sequences.

Mutation

A change in the nucleotide sequence of DNA, which can result in altered protein function and phenotypic effects.

Silent Mutation

A mutation that changes a codon but does not alter the resulting amino acid sequence, thus having no effect on the protein.

Missense Mutation

A mutation that changes a codon, resulting in a different amino acid being incorporated into the protein.

Nonsense Mutation

A mutation that changes a codon to a stop codon, leading to premature termination of translation and a truncated, often non-functional protein.

Conjugation

A process by which bacteria directly transfer genetic material (plasmids) to another bacterium, increasing genetic diversity.

Transduction

A process by which foreign DNA is introduced into a cell by a virus or viral vector, transferring genetic material between cells.

Genotype

The genetic makeup of an organism, including all the alleles it carries.

Phenotype

The observable characteristics of an organism, resulting from the interaction of its genotype with the environment.

Heredity

The transmission of traits from parents to offspring, allowing for genetic continuity across generations.

Genetics

The scientific study of heredity and variation in living organisms, exploring genes, inheritance, and genetic variation.

Locus

The specific physical location of a gene or other DNA sequence on a chromosome.

Homozygous

Having two identical alleles for a particular gene at a specific locus, resulting in consistent expression of the trait.

Heterozygous

Having two different alleles for a particular gene at a specific locus, which may result in dominant/recessive or codominant expression.

Pedigree

A diagram that shows the inheritance of a trait through several generations of a family, used to analyze inheritance patterns.

Sex-linked gene

A gene located on a sex chromosome (X or Y), showing different inheritance patterns in males and females.

Autosome

A chromosome that is not a sex chromosome, present in the same number and type in both males and females.

Haploid

A cell containing a single set of chromosomes (n), such as gametes (sperm and egg cells).

Diploid

A cell containing two sets of chromosomes (2n), one set inherited from each parent, typical of somatic cells.

Mitosis

A type of cell division that results in two daughter cells each having the same number and kind of chromosomes as the parent nucleus, typical of ordinary tissue growth.

Meiosis

A type of cell division that results in four daughter cells each with half the number of chromosomes as the parent cell, as in the production of gametes and plant spores.

Crossing Over

The exchange of genetic material between homologous chromosomes during prophase I of meiosis, resulting in recombinant chromosomes.

Independent Assortment

The random orientation and separation of homologous chromosomes during meiosis I, creating genetic variation in gametes.

Character

A heritable feature that varies among individuals, such as flower color or seed shape.

Trait

A specific variant of a character, like purple or white flower color.

Hybridization

The mating or crossing of two true-breeding varieties, resulting in hybrid offspring.

P Generation

The true-breeding parental generation in a genetic cross, used as the starting point for analysis.

F1 Generation

The first filial generation, which are the hybrid offspring resulting from a cross between the P generation.

F2 Generation

The second filial generation, resulting from self-pollination or cross-pollination of F1 hybrids.

Monohybrid Cross

A genetic cross between individuals heterozygous for one particular character.

Dihybrids

Individuals heterozygous for two characters being followed in a genetic cross.

Dihybrid Cross

A genetic cross between individuals who are heterozygous for two characters.

Law of Segregation

Mendel's law stating that two alleles for a heritable character separate during gamete formation and end up in different gametes.

Law of Independent Assortment

Mendel's law stating that each pair of alleles segregates independently of each other pair of alleles during gamete formation, applicable for genes on different chromosomes.

Complete Dominance

The situation in which the phenotype of the heterozygote and dominant homozygote are indistinguishable, with the dominant allele masking the recessive.

Incomplete Dominance

A form of inheritance where the phenotype of heterozygotes is intermediate between the phenotypes of individuals homozygous for either allele.

Codominance

A form of inheritance in which two alleles affect the phenotype in separate, distinguishable ways, with both traits being simultaneously expressed.

Pleiotropy

The ability of a single gene to have multiple effects on an individual's phenotype.

Epistasis

A phenomenon where a gene at one locus alters the phenotypic expression of a gene at a second locus.

Quantitative Characters

Characters that vary in the population along a continuum, often influenced by multiple genes and environmental factors.

Polygenic Inheritance

The additive effect of two or more genes on a single phenotype, leading to continuous variation.

Cellular Respiration

The catabolic pathways of aerobic and anaerobic respiration, breaking down organic molecules and using an electron transport chain for ATP production.

Photosynthesis

The process by which plants and other autotrophs convert light energy into chemical energy, synthesizing organic compounds from CO2 and water.

Mitosis Stages

The distinct phases of mitosis are prophase, prometaphase, metaphase, anaphase, and telophase, each with characteristic events in chromosome separation and cell division.

Meiosis Stages

Meiosis involves two rounds of division: Meiosis I (prophase I, metaphase I, anaphase I, telophase I) and Meiosis II (prophase II, metaphase II, anaphase II, telophase II), resulting in four haploid cells.

Cell Cycle

An ordered sequence of events in the life of a cell, from its origin in the division of a parent cell until its own division into two, including interphase and M phase.

Cell Cycle Checkpoints

Critical control points in the cell cycle (G1, S, G2, and M checkpoints) where signals regulate progression by assessing DNA integrity and cell conditions.

Macromolecules

Large polymeric molecules essential for life, including proteins, nucleic acids, carbohydrates, and lipids, each with distinct structures and functions.

Gene Expression

The process by which information encoded in DNA directs the synthesis of proteins or RNAs, influencing cell structure and function.

Evolution

Descent with modification; the idea that living species are descendants of ancestral ones that were different from present-day ones and is subject to natural selection.

Glycolysis

An ancient metabolic pathway in the cytoplasm that converts glucose into pyruvate, producing a small amount of ATP and NADH.

Krebs Cycle

Also known as the citric acid cycle, this stage of cellular respiration in the mitochondrial matrix oxidizes acetyl-CoA, generating ATP, NADH, and FADH2.

Electron Transport Chain

A series of protein complexes in the inner mitochondrial membrane that accepts electrons from NADH and FADH2, using their energy to pump protons and generate a gradient for ATP synthesis.

Light Reactions

The initial phase of photosynthesis where solar energy is converted to chemical energy in the form of ATP and NADPH, occurring in the thylakoid membranes.

Calvin Cycle

The second phase of photosynthesis in the stroma, where chemical energy (ATP and NADPH) is used to synthesize organic compounds from carbon dioxide through carbon fixation.

Prophase

The first stage of mitosis, characterized by chromosome condensation, spindle formation, and the breakdown of the nuclear envelope.

Metaphase

The stage of mitosis characterized by the alignment of chromosomes along the metaphase plate, ensuring equal distribution to daughter cells.

Anaphase

The stage of mitosis characterized by the separation of sister chromatids and their movement to opposite poles of the cell.

Telophase

The final stage of mitosis, where the nuclear envelope reforms around the separated chromosomes, and chromosomes decondense.

Cytokinesis

The division of the cytoplasm to form two separate daughter cells, usually occurring concurrently with telophase of mitosis.

G1 Phase

The first gap phase of the cell cycle, where the cell grows and prepares for DNA replication ensuring conditions are favorable for replication.

S Phase

The synthesis phase of the cell cycle, where DNA replication occurs, resulting in duplication of each chromosome.

G2 Phase

The second gap phase of the cell cycle, where the cell continues to grow and prepares for cell division accumulating necessary resources.

M Phase

The mitotic phase which includes mitosis and cytokinesis, resulting in the division of the cell into two genetically identical daughter cells.

Carbohydrates

Organic molecules consisting of sugars and polymers of sugars, serving as a primary source of energy and structural components.