Gemini Biology Study Guide Flashcards

A comprehensive set of biology vocabulary flashcards covering cell transport, bioenergetics, cell division, genetics, molecular biology, and evolution based on the provided study guide.

Homeostasis

The process by which biological systems maintain stability while adjusting to changing external conditions.

Diffusion

The movement of molecules from an area of higher concentration to an area of lower concentration.

Equilibrium

A state where the concentration of a substance is the same throughout a space.

Concentration gradient

The difference in the concentration of a substance across a distance or a membrane.

Osmosis

The diffusion of water through a selectively permeable membrane.

Phagocytosis

A type of endocytosis where a cell engulfs large particles or whole cells ("cell eating").

Endocytosis

The process by which a cell takes material into the cell by infolding of the cell membrane.

Exocytosis

The process by which a cell releases large amounts of material through a vesicle fusing with the membrane.

Active transport

The movement of materials through a cell membrane using energy (ATP), usually against the concentration gradient.

Passive transport

The movement of materials across a cell membrane without the use of energy by the cell.

Isotonic

A solution where the concentration of solutes is equal inside and outside the cell; no net water movement.

Hypertonic

A solution with a higher concentration of solutes than the cell; causes the cell to shrink as water leaves.

Hypotonic

A solution with a lower concentration of solutes than the cell; causes the cell to swell as water enters.

Facilitated diffusion

Movement of specific molecules across cell membranes through protein channels (still passive transport).

Chlorophyll

The primary green pigment in plants that absorbs light energy for photosynthesis.

Reactants of photosynthesis

Water ($H_2O$), Carbon Dioxide ($CO_2$), and Light energy.

Products of photosynthesis

Glucose ($C_6H_{12}O_6$) and Oxygen ($O_2$).

Reactants of cellular respiration

Glucose and Oxygen.

Products of cellular respiration

Carbon Dioxide, Water, and ATP (energy).

Fermentation

An anaerobic process (without oxygen) that allows glycolysis to continue by producing ATP.

ADP (Adenosine Diphosphate)

A lower-energy molecule that can be converted into ATP by adding a phosphate group.

ATP (Adenosine Triphosphate)

The main energy source that cells use for most of their work.

Thylakoid

Sack-like photosynthetic membranes found in chloroplasts where light-dependent reactions occur.

Stroma

The fluid portion of the chloroplast, outside of the thylakoids, where the Calvin cycle occurs.

NADP⁺/NAD⁺

Electron carrier molecules that transport high-energy electrons during metabolic processes.

Light-dependent reactions

The first stage of photosynthesis that uses energy from light to produce ATP and NADPH.

Light-independent reactions (Calvin Cycle)

The stage of photosynthesis that uses ATP and NADPH to build high-energy compounds like sugar.

Chloroplast

The organelle where photosynthesis takes place.

Pigments

Light-absorbing molecules used by plants to gather the sun's energy.

Anaerobic respiration

The process of producing energy without the presence of oxygen.

Aerobic respiration

The process of producing energy that requires oxygen.

Glycolysis

The first step in releasing the energy of glucose, in which a molecule of glucose is broken into two molecules of pyruvic acid.

Krebs cycle

The second stage of cellular respiration, in which pyruvic acid is broken down into carbon dioxide in a series of energy-extracting reactions.

Mitochondria

The organelle known as the "powerhouse" of the cell where ATP is produced through respiration.

Unicellular organisms

Organisms consisting of only one cell.

Prokaryotes

Unicellular organisms that lack a nucleus and membrane-bound organelles.

Chromosome

Threadlike structures made of DNA molecules that contain the genes.

Chromatid

One of two identical "sister" parts of a duplicated chromosome.

Chromatin

The granular material you see in the nucleus; consists of DNA tightly coiled around proteins.

Centriole

Structure in an animal cell that helps to organize cell division.

Prophase

First and longest phase of mitosis; chromatin condenses into chromosomes and the nuclear envelope breaks down.

Metaphase

Second phase of mitosis; chromosomes line up across the center of the cell.

Anaphase

Third phase of mitosis; sister chromatids separate and move toward opposite poles.

Telophase

Final phase of mitosis; distinct individual chromosomes begin to spread out into a tangle of chromatin.

Interphase

The period of the cell cycle between cell divisions (G1, S, and G2 phases).

Cytokinesis

Division of the cytoplasm to form two separate daughter cells.

Cell plate

A structure that forms during cytokinesis in plant cells to separate the two daughter cells.

Cancer

A disorder in which some of the body's cells lose the ability to control growth.

Tumor

A mass of rapidly dividing cells that can damage surrounding tissue.

Spindle fibers

Fanlike microtubule structures that help separate the chromosomes during mitosis.

Centromere

Area where the chromatids of a chromosome are attached.

Stem cells

Unspecialized cells from which differentiated cells develop.

Differentiation

Process in which cells become specialized in structure and function.

Autosomes

Chromosomes that are not directly involved in determining the sex of an individual (pairs 1–22 in humans).

Sex chromosomes

Chromosomes that determine the individual's sex (X and Y).

Karyotype

A micrograph (picture) of the complete diploid set of chromosomes grouped together in pairs.

Trisomy

A condition in which an individual has three copies of a particular chromosome instead of two (e.g., Down Syndrome).

Recessive

An allele that is masked when a dominant allele is present.

Dominant

An allele that is always expressed if present.

Phenotype

The physical characteristics of an organism.

Genotype

The genetic makeup of an organism (e.g., Bb).

Trait

A specific characteristic of an individual.

Allele

One of a number of different forms of a gene.

Punnett square

A diagram used to predict the genotype and phenotype combinations of a genetic cross.

Incomplete dominance

Situation in which one allele is not completely dominant over another (results in a blend, like pink flowers).

Codominance

Situation in which the phenotypes produced by both alleles are completely expressed (e.g., spotted animals).

Multiple alleles

A gene that has more than two alleles (e.g., Blood types).

Gene

A sequence of DNA that codes for a protein and thus determines a trait.

Homozygous

Having two identical alleles for a particular gene (AA or aa).

Heterozygous

Having two different alleles for a particular gene (Aa).

Sexual reproduction

Type of reproduction in which cells from two parents unite to form the first cell of a new organism.

Asexual reproduction

Process by which a single parent reproduces by itself.

Genetic diversity

The total number of genetic characteristics in the genetic makeup of a species.

Meiosis

Process in which the number of chromosomes per cell is cut in half through the separation of homologous chromosomes in a diploid cell.

Gamete

Specialized cell involved in sexual reproduction (sperm or egg).

Mutation

A change in the genetic material of a cell.

DNA

Deoxyribonucleic acid; the carrier of genetic information.

Nucleotides

The building blocks of nucleic acids, consisting of a 5-carbon sugar, a phosphate group, and a nitrogenous base.

Deoxyribose

The five-carbon sugar found in DNA.

Double helix

The shape of DNA; two strands wound around each other like a twisted ladder.

Nitrogen base

Adenine (A), Thymine (T), Guanine (G), and Cytosine (C).

DNA replication

The process of making a copy of DNA.

Transcription

The process where the DNA sequence in a gene is copied into mRNA.

Ribosome

The organelle where protein synthesis occurs.

Translation

The process where genetic information coded in mRNA is used to assemble a protein.

mRNA (Messenger RNA)

Carries instructions for polypeptide synthesis from nucleus to ribosomes.

tRNA (Transfer RNA)

Carries amino acids to the ribosome and matches them to the coded mRNA message.

Codon

A three-nucleotide sequence on mRNA that codes for a single amino acid.

Anticodon

Group of three bases on a tRNA molecule that are complementary to an mRNA codon.

Polypeptide

A long chain of amino acids that makes proteins.

Uracil

A nitrogenous base found in RNA but not in DNA (replaces Thymine).

Darwin

The scientist who formulated the theory of evolution by natural selection.

Natural selection

Process by which individuals that are better suited to their environment survive and reproduce most successfully.

Fitness

How well an organism can survive and reproduce in its environment.

Geographic isolation

Form of reproductive isolation in which two populations are separated physically by geographic barriers.

Vestigial structure

Structure that is inherited from ancestors but has lost much or all of its original function (e.g., human appendix).

Homologous structure

Structures that are similar in different species of common ancestry (e.g., arm bones in humans and wings in bats).

Convergent evolution

Process by which unrelated organisms independently evolve similarities when adapting to similar environments.

Divergent evolution

When two or more species sharing a common ancestor become more different over time.