Midterm Bio Review

Biology

The scientific discipline that investigates living organisms, their interactions, and the processes that sustain life.

Evidence

A comprehensive collection of data derived from scientific experiments, observations, and measurements that support or refute a hypothesis.

Quantitative Observations

Data obtained through numerical measurements and counting, which can be statistically analyzed.

Qualitative Observations

Descriptive data that cannot be measured numerically, often involving characteristics like color, texture, or behavior.

Inference

A logical conclusion drawn from observations and prior knowledge, often used to generate hypotheses.

Hypothesis

A proposed explanation or educated guess based on limited evidence, intended to be tested and validated through experimentation.

Variable

Any factor, trait, or condition that can exist in differing amounts or types within an experiment.

Independent Variable

The experimental variable that the researcher deliberately manipulates to observe its effect on the dependent variable.

Dependent Variable

The outcome variable that is measured and assessed in response to changes made to the independent variable.

Experimental Group

The set of subjects in an experiment that is exposed to the treatment or condition being tested.

Control Group

A baseline group in an experiment that remains unaltered to provide a comparison against the experimental group.

Scientific Theory

A well-substantiated explanation of an aspect of the natural world, based on a body of evidence that has stood up to testing and scrutiny.

Scientific Law

A statement that describes a consistent and universal phenomenon, often expressed mathematically, within the field of science.

Homeostasis

The regulatory process by which biological systems maintain a stable internal environment despite external changes.

Metabolism

The complete range of biochemical processes that occur within a living organism to maintain life, including energy conversion and material processing.

Anabolism

The metabolic pathways that construct molecules from smaller units, requiring energy to synthesize essential compounds.

Catabolism

The set of metabolic pathways that break down complex molecules into simpler ones, releasing energy in the process.

Autotrophs

Organisms capable of producing their own food from inorganic substances, using light or chemical energy through processes like photosynthesis.

Heterotrophs

Organisms that cannot produce their own food and rely on consuming other organisms, either directly or indirectly, for energy.

Prokaryotic Cell

A simple, unicellular organism that lacks a distinct nucleus and membrane-bound organelles, typically microscopic.

Eukaryotic Cell

A complex cell characterized by the presence of a membrane-bound nucleus and specialized organelles.

Plasma Membrane

The selectively permeable lipid bilayer that surrounds and protects the cell's interior, regulating the passage of substances.

Cytoplasm

The gel-like substance within a cell, excluding the nucleus, that contains organelles and is the site of many metabolic reactions.

Ribosomes

Cellular structures responsible for protein synthesis, composed of ribosomal RNA (rRNA) and proteins.

Endoplasmic Reticulum (ER)

An extensive, membranous network within the cell that synthesizes proteins and lipids, characterized by rough (with ribosomes) and smooth (without ribosomes) regions.

Golgi Apparatus

An organelle that processes, sorts, and delivers proteins and lipids from the endoplasmic reticulum to their final destinations.

Vacuole

A large, membrane-bound space within a cell used for storage of substances such as nutrients, waste products, or water.

Mitochondria

Double-membraned organelles known as the powerhouses of the cell, where aerobic respiration takes place to produce ATP, the main energy currency.

Lysosome

Organelles containing digestive enzymes that break down waste materials and cellular debris.

Chloroplasts

Organelles found in plant cells and some protists, responsible for photosynthesis, converting light energy into chemical energy.

Mutation

An alteration in the DNA sequence of an organism's genome, which can lead to changes in phenotype or gene function.

Atom

The smallest unit of matter, consisting of a nucleus surrounded by electrons, foundational to all chemical elements.

Molecule

A chemical entity formed when two or more atoms bond together, representing the smallest fundamental unit of a chemical compound.

Ionic Bond

A type of chemical bond formed through the transfer of electrons from one atom to another, resulting in the attraction between positively and negatively charged ions.

Covalent Bond

A chemical bond formed when atoms share electrons to achieve stable electron configurations.

Cell Theory

A fundamental biological principle stating that all living organisms are composed of cells, and that cells are the basic unit of life.

Cytology

The branch of biology that focuses on the study of cells' structure, function, and properties.

Chromatin

A complex of DNA and protein found in the nucleus of a cell that condenses to form chromosomes during cell division.

Microtubules

Hollow, tubular structures made of protein that help maintain cell shape and are involved in intracellular transport and cell division.

Centrioles

Cylindrical organelles that play a critical role in cell division by organizing the spindle fibers that separate chromosomes.

Nucleus

The membrane-bound organelle that holds the cell's genetic material (DNA) and regulates gene expression and cell division.

Mendelian Genetics

The study of inheritance patterns based on the principles established by Gregor Mendel, delineating how traits are passed from parents to offspring.

True-breeding

Refers to organisms that consistently produce offspring with the same phenotype when they self-pollinate or cross with others of the same variety.

Self-Pollination

A reproductive process in flowering plants wherein pollen from the same flower or plant fertilizes its own ovules.

Allele

Different forms of the same gene that occupy the same position on homologous chromosomes, contributing to the organism's genotype.

Genotype

The specific genetic constitution or alleles of an organism represented as a two-letter code reflecting the alleles for a particular trait.

Phenotype

The observable characteristics or traits of an organism, determined by the interaction of its genotype with the environment.

Homozygous genotype

A genetic condition in which an organism has two identical alleles for a specific trait.

Heterozygous genotype

A genetic condition in which an organism possesses two different alleles for a specific trait.

Dominant allele

An allele that expresses its phenotype even when only one copy is present in the genotype.

Recessive allele

An allele that only expresses its phenotype when two copies are present in the genotype; its trait is masked by a dominant allele.

Punnett Square

A graphical method used to predict the genotypic and phenotypic outcomes of a genetic cross by displaying all potential allele combinations.

Testcross

A genetic cross used to determine the genotype of an organism expressing a dominant phenotype by crossing it with a homozygous recessive organism.

Pedigree

A diagram that illustrates the inheritance of a particular trait through multiple generations within a family.

Monohybrid cross

A genetic cross between individuals focusing on one specific trait or characteristic, providing insight into the inheritance patterns of that trait.

Dihybrid cross

A breeding experiment examining the inheritance of two distinct traits simultaneously to analyze their individual inheritance patterns.

Law of independent assortment

The genetic principle stating that genes located on different chromosomes are inherited independently from one another during gamete formation.

Autosomes

Chromosomes that are not involved in determining the sex of an organism; they make up the majority of the chromosome set in most species.

Sex chromosomes

Chromosomes responsible for determining the biological sex of an individual, typically labeled as X and Y in humans.

Carriers

Individuals who possess one recessive allele for a trait but do not exhibit the trait themselves, allowing for transmission to offspring.

Incomplete dominance

A genetic scenario where the phenotype of heterozygotes is intermediate between the phenotypes of the two homozygotes.

Epistasis

A complex gene interaction where the phenotypic expression of one gene is modified or masked by another gene that is independently inherited.

Pleiotropy

A genetic phenomenon in which a single gene influences multiple, seemingly unrelated phenotypic traits.

Blood types

Classifications of human blood based on the presence or absence of specific antigens on the surface of red blood cells, primarily A, B, AB, and O types.

Multiple allele trait

A genetic trait that is governed by one gene having more than two possible alleles, leading to a variety of phenotypes.

Codominance

A genetic inheritance pattern where both alleles contribute equally and distinctly to the organism's phenotype.

Antigen

Any substance that triggers an immune response, particularly the production of antibodies, when recognized as foreign by the body.

Antibody

Proteins produced by the immune system that specifically identify and neutralize antigens or pathogens.

Rh factor

An inherited protein that may be present on the surface of red blood cells, determining Rh positivity or negativity in blood type.

Rh-positive

Refers to blood that contains the Rh factor antigen indicating the presence of the specific protein on red blood cells.

Autosomal inheritance

The transmission of genetic traits carried on the non-sex chromosomes, affecting both genders equally.

Rh negative

Indicates the absence of the Rh factor antigen on red blood cells, classifying blood type as Rh-negative.

Sex-linked inheritance

Genetic inheritance patterns where genes are located on the sex chromosomes, leading to different expression in males and females.

Allele mutation

A significant alteration in the structure of a gene that can affect the functioning and expression of a genetic trait.

Changes in chromosome structure

Alterations in the structural integrity of chromosomes that can result in loss, duplication, or rearrangement of genetic material.

Changes in chromosome number

Abnormal variations in the number of chromosomes, potentially resulting in genetic disorders when chromosomes are gained or lost.

Genetic disease carrier

An individual who carries a recessive allele for a genetic disorder and can pass it to offspring without showing symptoms of the disorder.

Huntington's disease

A neurodegenerative genetic disorder caused by a dominant allele leading to progressive cognitive and motor decline, typically manifesting later in life.

Mutated

Describes a gene or organism that has undergone a significant alteration in its DNA sequence.

Gene mutation

Any change affecting the nucleotide sequence of a gene, possibly impacting the encoded protein's structure and function.

Silent mutation

A type of gene mutation that does not change the amino acid sequence of the resulting protein despite altering the DNA sequence.

Mutation: Insertion

A mutation where one or more nucleotides are added to a DNA sequence, potentially altering protein function.

Substitution mutation

A mutation where one nucleotide is replaced by another, which may lead to changes in the amino acid sequence of a protein.

Mutation: Deletion

A type of mutation where one or more nucleotides are removed from a DNA sequence, which can disrupt normal gene function.

Frameshift mutation

A genetic mutation that occurs due to the insertion or deletion of nucleotides, shifting the reading frame of the DNA sequence.

Chromosomal mutation

A mutation involving a change in the structure or number of chromosomes, affecting the genome by gaining or losing genetic material.

Cri du chat

A genetic disorder caused by a deletion on the short arm of chromosome 5, characterized by severe developmental issues and a distinctive cry.

Deletion mutation

The loss of a segment of DNA from a chromosome during cell division, which can lead to gene loss and function disruption.

Duplication chromosomal mutation

A mutation in which a segment of a chromosome is duplicated, resulting in multiple copies of a particular gene or set of genes.

Inversion mutation (chromosomal)

A mutation where a chromosome segment breaks off, flips around, and reattaches, reversing the genetic sequence.

Translocation chromosomal mutation

A genetic mutation involving the rearrangement of parts between nonhomologous chromosomes, potentially disrupting gene function.

Nondisjunction

An error in cell division during meiosis or mitosis in which chromosomes do not separate properly, leading to gametes with abnormal chromosome numbers.

Genome

The complete set of genetic material of an organism, encompassing all of its genes and non-coding sequences within its DNA.

Short tandem repeats (STRs)

Repeating sequences of DNA that vary in number among individuals, often used in DNA profiling and forensic analysis.

Restriction enzymes

Proteins that recognize specific nucleotide sequences in DNA and cleave the DNA at these sites, essential for genetic engineering and cloning.

Plasmid

A small, circular piece of DNA commonly found in bacteria, capable of replicating independently and often used in genetic engineering.

Recombinant DNA

DNA formed by combining DNA from different sources, allowing for the study and manipulation of genes for research and medical purposes.

Molecular cloning

The process of making multiple identical copies of a specific DNA fragment, enabling detailed study or production of proteins.

Genetically modified organisms

Living organisms whose genetic material has been artificially manipulated in a laboratory setting through genetic engineering.

Transgenic organism

An organism that contains a gene or genes which have been artificially inserted instead of the organism acquiring them through reproduction.