Biology Vocabulary Review

Flashcards covering key vocabulary from a biology lecture to help students review their notes and prepare for an exam.

Made of cells

Being made up of one or more cells, the basic unit of life.

Growth and development

An organism increasing in size and complexity over time.

Response to their environment (stimulus)

Detecting and reacting to changes in the environment.

Based on a universal genetic code

Passing on genetic information from parent to offspring.

As a group, evolve over time

Gradual change over time, referring to the process where characteristics within a population change across generations due to natural selection.

Require nutrients and energy (metabolism)

Chemical processes within an organism to acquire and use energy.

Homeostasis

Maintaining a stable internal environment despite external changes.

Reproduce

The ability to create new individuals of the same species.

Independent Variable

The variable that the researcher actively changes or manipulates to observe its effect on another variable; considered the "cause" in a cause-and-effect relationship.

Dependent Variable

The variable that is measured or observed to see how it is affected by changes in the independent variable; considered the "effect" in a cause-and-effect relationship.

Controlled Variable

A variable that is kept at the same level in every group so comparisons can be made to see if changes in the dependent variable are due only to changes in the independent variable.

Control Group

A group in an experiment that does not receive the experimental treatment or variable being tested, serving as a baseline for comparison with the experimental group

Biodiversity

The variety of life on Earth at all its levels, from genes to ecosystems, and can encompass the evolutionary, ecological, and cultural processes that sustain life.

Energy flows but matter cycles

Energy is neither created nor destroyed, but passes from organism to organism as one eats another, as well as out into the atmosphere. Most energy is lost as heat. The source of all energy on earth is the sun. Matter is neither created nor destroyed; All of the carbon (C), hydrogen (H), oxygen (O), nitrogen (N) and phosphorus (P) on earth was here when earth formed. All matter gets incorporated into living things, is passed from organism to organism as one eats another and is put back into the earth when organisms die and decompose.

Competition

Organisms or species interact to obtain a resource that is in limited supply.

Habitat

The physical location where an organism lives, like a forest or a coral reef.

Niche

The specific role an organism plays within its environment, including its food sources, behavior patterns, and interactions with other species; essentially, its "job" in the ecosystem

Keystone species

Plays a disproportionately large role in maintaining the balance of an ecosystem, meaning their presence significantly impacts the biodiversity of the area by controlling populations of other species.

Evolution

Change over time; the process by which modern organisms have descended from ancient organisms

Variation

Differences in traits or characteristics among individuals within a population

Adaptation

Heritable characteristic that increases an organism’s ability to survive and reproduce in an environment

Fitness

How well an organism can survive and reproduce in its environment

Natural selection

Process by which organisms that are most suited to their environment survive and reproduce most successfully; also called survival of the fittest.

Homologous structures

Anatomical features found in different species that share a similar basic structure and origin, indicating a common evolutionary ancestor, even if they serve different functions in the present-day organisms due to different environments/niches

Analogous structures

Anatomical features that perform similar functions in different species that do not share a common ancestor, due to their similar environment/niches

Divergent evolution

Species with a shared ancestry evolve different adaptations based on their respective environments

Convergent evolution

Species adapt to similar environmental pressures in similar ways; similar traits are not due to a common ancestor

Sexual selection

A type of natural selection that arises from differences in reproductive success based on certain traits that increase an individual's chances of attracting mates or successfully reproducing. These traits may enhance mating opportunities but do not necessarily improve survival.

Species

Group of similar organisms that can breed and produce fertile offspring

Prokaryotic vs Eukaryotic Cell

A prokaryotic cell lacks a nucleus and other membrane-bound organelles, while a eukaryotic cell has a well-defined nucleus where its DNA is stored, along with other membrane-bound organelles that compartmentalize cellular functions

Organelle

A structure within a cell that has one or more specific jobs to perform in the cell, much like an organ does in the body

Mitochondria

Convert glucose into ATP energy using cellular respiration

Chloroplasts

Convert energy in sunlight into glucose using photosynthesis

Ribosomes

Protein production

Cell Membrane

Separates the cell from its environment

Cell Wall

Provides structural support and protection to a cell

Ionic bond vs. Covalent Bond

Form when one atom transfers electrons to another atom. Form when two atoms share electrons.

Water molecule

A molecule that contains covalent bonds, where electrons are shared between atoms. In water (H₂O), the oxygen atom shares electrons with two hydrogen atoms, but oxygen pulls the shared electrons more strongly than hydrogen. This causes the electrons to be closer to oxygen, creating an uneven distribution of charge

Hydrogen bond

The positive hydrogen of one water molecule is attracted to the negative oxygen of another water molecule. This weak attraction between molecules

Diffusion

Movement of molecules from an area of high concentration to low concentration. It happens naturally and does not require energy

Polar Molecule

A molecule that has uneven sharing of electrons, resulting in partial positive and negative ends. Polar molecules mix well with water (hydrophilic)

Non-polar Molecule

A molecule where electrons are shared evenly, so there are no charged ends. Non-polar molecules do not mix well with water (hydrophobic)

G1 (first cell growth phase)

Grows and performs its normal functions; Organelles and proteins are made

S (Synthesis)

Replicates its DNA, making an identical copy of each chromosome

G2 (second cell growth phase)

Continues to grow; Produces proteins and organelles needed for mitosis

Prophase

Chromosomes condense and become visible. Spindle fibers start to form and attach to centromeres; The nuclear envelope breaks down.

Metaphase

Chromosomes line up in the middle of the cell (equator) based on pulling by the spindle

Anaphase

Sister chromatids are pulled apart by the spindle fibers. They move to opposite ends (poles) of the cell.

Telophase

Chromatids reach the poles and begin to uncoil back into chromatin. Nuclear envelopes re-form around each set of DNA.

Cytokinesis

Cytoplasm divides, creating two separate daughter cells

Mitosis

Division of nucleus and its chromosomes into two identical nuclei

Cytokinesis

Division of the cytoplasm, resulting in two separate cells

Checkpoints

Ensure the cell is ready to move to the next phase of the cell cycle. They help prevent errors like damaged DNA or incomplete replication.

G1 Checkpoint

Checks for cell size, nutrients, growth signals, and DNA damage.

S/G2 Checkpoint

Ensures all DNA is replicated correctly and checks for damage.

M (Spindle) Checkpoint

Ensures chromosomes are properly attached to the spindle before anaphase.

Angiogenesis

Formation of new blood vessels

Reactants

Substances that enter a chemical reaction

Products

Substances formed by the reaction

Activation energy

The minimum energy needed to start a chemical reaction

Enzyme

Enzymes lower the activation energy, allowing reactions to happen faster and more efficiently.

Enzyme Structure

The enzyme’s shape determines its function. If the shape changes, the substrate may not fit in the active site, and the enzyme won't work.

Denaturation

When an enzyme loses its shape, making it unable to bind to its substrate.

Cellular Respiration

glucose + oxygen -> carbon dioxide + water, C6H12O6 +6 O2 ——>6 CO2+ 6 H2O

Photosynthesis

Carbon dioxide + water -> glucose + oxygen, 6 CO2+ 6 H2O ——> C6H12O6 +6 O2

Aerobic

Describes metabolic processes that require oxygen

Gene

A segment of DNA that contains the instructions to make a specific protein

Allele

A different version of a gene

Genotype

The combination of alleles an organism has for a trait (e.g., TT, Tt, or tt)

Phenotype

The physical trait that shows up, based on the genotype (e.g., tall or short)

Dominant

An allele that shows its effect even if only one copy is present (written as a capital letter, like T)

Recessive

An allele that only shows its effect if both copies are the same (written as a lowercase letter, like t)

Homozygous allele pair

Two of the same alleles for a gene

Heterozygous allele pair

Two different alleles for a gene

Incomplete dominance

heritance where neither allele is completely dominant, so the result is a blended/ in between phenotype

Codominance

Both alleles are fully and equally expressed in the phenotype

Sex-linked gene

Inheritance of a gene on the X chromosome. These traits often show up more in males because they have only one X

Hardy-Weinberg equation

p²+ 2pq+ q² = 1

q

Represents the frequency of the recessive allele

p

Represents the frequency of the dominant allele

q2

Represents the frequency of the homozygous recessive genotype

p2

Represents the frequency of the homozygous dominant genotype

2pq

Represents the frequency of the heterozygous genotype

No Mutations

The DNA of individuals must not change.

Random Mating

Individuals must pair by chance, not by choosing certain traits.

No Natural Selection

All traits must give equal chances of survival and reproduction.

Extremely Large Population Size

To prevent changes by chance (genetic drift).

No Gene Flow

No new individuals can enter or leave the population.

Unzipping

The DNA double helix is unwound by helicase. Hydrogen bonds between base pairs are broken, creating two single strands.

Building

DNA polymerase adds complementary DNA nucleotides to the original strands.

Proofreading

DNA polymerase checks for and corrects errors.

Transcription

Process of making mRNA using the DNA template

Translation

Process of making a polypeptide chain using the mRNA

Substitution (Point Mutation)

One nucleotide is replaced by another. May result in a different amino acid, or sometimes no change at all (silent mutation).

Insertion

One or more nucleotides are added to the DNA sequence. This can cause a frameshift, changing the way the codons are read during translation and resulting in a new set of amino acids.

Deletion

One or more nucleotides are removed from the DNA sequence. Like insertion, this can cause a frameshift and significantly change the resulting protein.

Restriction enzymes

Cut DNA at specific sequences. This creates DNA fragments of different lengths. When used in gel electrophoresis, these fragments are separated by size, allowing scientists to compare DNA samples or analyze genetic differences.

Stem cells

Unspecialized cells that can divide and become many different types of differentiated cells. In regeneration, stem cells help replace damaged or lost tissues by turning into the needed cell types (like skin, nerve, or muscle cells).

PCR (Polymerase Chain Reaction)

Technique that makes millions of copies of a specific DNA segment. It's useful for things like DNA testing, disease detection, forensics, and research where only a small DNA sample is available.

CRISPR

Gene-editing tool that allows scientists to cut and modify specific DNA sequences in an organism. It is useful for fixing genetic disorders, studying genes, modifying crops, and developing treatments for diseases.