Biology Midterm Exam Review 2025

A comprehensive set of vocabulary flashcards covering essential biological concepts for midterm exam preparation.

Dominant Trait

A trait that will appear in the phenotype even if only 1 copy of the allele is present.

Recessive Trait

A trait that will only appear in the phenotype if 2 copies of the allele are present.

Heterozygous

An organism with 2 different alleles for a specific trait.

Gametes

Reproductive cells that carry \frac{1}{2} the number of chromosomes of a normal cell.

Regeneration

The process by which organisms can regrow lost body parts.

Energy Storage Molecule

The molecule in which energy is stored; in photosynthesis, this is usually glucose.

Photosynthesis

The process by which plants convert light energy into chemical energy.

Meiosis

A type of cell division that reduces the chromosome number by \frac{1}{2}, creating gametes.

Mitosis

The process of cell division that results in 2 identical daughter cells.

Polypeptide

A chain of amino acids that make up proteins.

Carbo-loading

The practice of consuming carbohydrates in excess before an endurance event.

Stem Cells

Undifferentiated cells that have the potential to develop into different cell types.

Diffusion

The process by which molecules spread from areas of high concentration to low concentration.

Osmosis

The diffusion of water molecules through a selectively permeable membrane.

Enzyme

A protein that acts as a catalyst to speed up chemical reactions.

Crossing-over

The exchange of genetic material between homologous chromosomes during meiosis.

DNA Replication

The process of making copies of DNA before a cell divides.

RNA

A nucleic acid that is involved in protein synthesis.

Amino Acid Sequence

The order of amino acids in a polypeptide chain.

Nucleotide

The basic building block of nucleic acids, consisting of a sugar, phosphate group, and a nitrogenous base.

Gene Mutation

A change in the DNA sequence that can lead to variations in traits.

Phenotype

The observable physical or biochemical characteristics of an organism.

Genotype

The genetic constitution of an individual organism.

Biomolecule

A molecule that is produced by living organisms, including proteins, nucleic acids, carbohydrates, and lipids.

Cytoplasm

The gel-like substance within the cell membrane that contains organelles.

Lysosome

An organelle containing enzymes that digest waste materials and cellular debris.

Mitochondria

Organelles known as the powerhouses of the cell, responsible for energy production.

Vacuole

A storage organelle in cells that can hold various substances.

Golgi Complex

An organelle that modifies, sorts, and packages proteins and lipids for secretion.

Endoplasmic Reticulum

An organelle involved in the synthesis of proteins and lipids.

Ribosome

A cellular structure that performs protein synthesis.

Chloroplast

An organelle found in plants and some algae that conducts photosynthesis.

Virus

A microscopic infectious agent that can only replicate inside a host cell.

Passive Transport

The movement of substances across a cell membrane without the use of cellular energy.

Facilitated Diffusion

A process by which substances move across a membrane with the help of a carrier protein.

Nonsense Mutation

A mutation that creates a premature stop codon in the DNA sequence.

Cell Cycle

The series of phases that a cell goes through to grow and divide.

Mutation

A change in the DNA sequence that can lead to genetic diversity.

Chromosome

A structure made of DNA and proteins, found in the nucleus of eukaryotic cells.

Enzyme Activity

The rate at which an enzyme catalyzes a reaction, which can be affected by various factors.

Gene Expression

The process by which the information in a gene is used to create a functional product, like a protein.

Chromatography

A technique used to separate components of a mixture based on their different interactions with a stationary phase.

Recessive Gene

A gene that is expressed in the phenotype only when 2 copies are present.

The Biomolecule used for Hibernation

Lipids, because of long term energy, and fats.

Biological Function

The biological role a biomolecule plays in the maintenance of life.

Cell Division

The process by which a parent cell divides into 2 or more daughter cells.

Cell Membrane

A semi-permeable biological membrane composed of a phospholipid bilayer that regulates the passage of substances in and out of the cell.

ATP (Adenosine Triphosphate)

The primary energy currency of the cell, providing energy for many biochemical processes.

Active Transport

The movement of substances across a cell membrane against a concentration gradient, requiring the expenditure of energy in the form of ATP.

Transcription

The first step of gene expression, where a particular segment of DNA is copied into mRNA by the enzyme RNA polymerase.

Translation

The process in which ribosomes decode mRNA to produce a specific amino acid chain, or polypeptide.

Eukaryote

An organism whose cells have a nucleus enclosed within a nuclear envelope and contain membrane-bound organelles.

Prokaryote

A simple, single-celled organism that lacks a nucleus and membrane-bound organelles, such as bacteria.

Cellular Respiration

The process by which cells break down glucose and other molecules to produce energy in the form of ATP.

Homeostasis

The process by which biological systems tend to maintain stability while adjusting to conditions that are optimal for survival.

Allele

1 of 2 or more alternative forms of a gene that arise by mutation and are found at the same place on a chromosome.

Cell Membrane

A semi-permeable biological membrane composed of a phospholipid bilayer that regulates the passage of substances in and out of the cell.

ATP (Adenosine Triphosphate)

The primary energy currency of the cell, providing energy for many biochemical processes.

Active Transport

The movement of substances across a cell membrane against a concentration gradient, requiring the expenditure of energy in the form of ATP.

Transcription

The first step of gene expression, where a particular segment of DNA is copied into mRNA by the enzyme RNA polymerase.

Translation

The process in which ribosomes decode mRNA to produce a specific amino acid chain, or polypeptide.

Eukaryote

An organism whose cells have a nucleus enclosed within a nuclear envelope and contain membrane-bound organelles.

Prokaryote

A simple, single-celled organism that lacks a nucleus and membrane-bound organelles, such as bacteria.

Cellular Respiration

The process by which cells break down glucose and other molecules to produce energy in the form of ATP.

Homeostasis

The process by which biological systems tend to maintain stability while adjusting to conditions that are optimal for survival.

Allele

1 of 2 or more alternative forms of a gene that arise by mutation and are found at the same place on a chromosome.

Hypertonic Solution

A solution with a higher concentration of solutes than another solution, resulting in water moving out of a cell.

Hypotonic Solution

A solution with a lower concentration of solutes than another solution, resulting in water moving into a cell.

Isotonic Solution

A solution with an equal concentration of solutes compared to another solution, resulting in no net movement of water.