Biology Practice Flashcards: Cell Theory, Cell Cycle, Meiosis, Transport, and Recombination

Vocabulary flashcards covering modern cell theory, cell cycle phases and checkpoints, meiosis, passive cell transport, and genetic recombination.

Robert Hooke (1665)

English scientist who coined the term 'cell' in 1665 after observing cork tissue.

Francesco Redi (1668)

Scientist who disproved spontaneous generation in 1668, supporting the concept of biogenesis.

Matthias Schleiden (1838)

Botanist who stated in 1838 that all plants are composed of cells.

Theodor Schwann (1839)

Zoologist who stated in 1839 that all animals are composed of cells.

Rudolf Virchow (1855)

Scientist who stated in 1855 that all cells arise only from pre-existing cells.

Louis Pasteur (1860s)

Scientist who disproved spontaneous generation using his swan-neck flask experiment in the 1860s.

Avery, MacLeod, and McCarty (1944)

Scientists who demonstrated in 1944 that DNA is the genetic material.

Hershey and Chase (1952)

Scientists who confirmed in 1952 that DNA carries hereditary genetic information.

Modern Cell Theory

Expanded cell theory stating that all living things are composed of cells, the cell is the basic structural and functional unit of life, all cells come from pre-existing cells, and energy flow and heredity (DNA) occur within cells.

Interphase

The longest, growth and preparation stage of the cell cycle (90% of the cycle) consisting of G1, S, and G2 phases, where the cell is active but not dividing.

G1 Phase

The first growth phase of interphase where the cell grows larger and synthesizes proteins and organelles.

S Phase (Synthesis)

The middle phase of interphase where DNA is copied so each chromosome consists of two sister chromatids.

G2 Phase

The final phase of interphase where the cell grows further and prepares for division.

M-Phase (Mitosis)

The stage of nuclear division comprising prophase, metaphase, anaphase, and telophase to divide genetic material equally.

Cytokinesis

The division of the cytoplasm that completes cell division, forming two daughter cells via a cleavage furrow in animal cells or a cell plate in plant cells.

G1 Checkpoint

A control point in the cell cycle that evaluates whether the cell is sufficiently large and contains undamaged DNA.

G2 Checkpoint

A quality-control point that verifies whether DNA was accurately copied during the S phase before entering mitosis.

M (Spindle) Checkpoint

A cell cycle checkpoint that ensures all chromosomes are correctly attached to the spindle apparatus before chromatid separation.

Meiosis

A specialized type of cell division occurring in reproductive organs that produces four genetically unique haploid daughter cells (gametes) with half the original chromosome count.

Gamete

A haploid reproductive cell, such as a sperm or egg cell, that contains half the normal number of chromosomes.

Homologous Chromosomes

A pair of chromosomes carrying the same genes at corresponding positions, though they may carry different versions (alleles).

Synapsis

The close pairing of homologous chromosomes during Prophase I of meiosis.

Tetrad

A structural unit formed during Prophase I composed of two paired homologous chromosomes, totaling four chromatids.

Crossing Over

The process occurring in Prophase I of meiosis where non-sister chromatids of homologous chromosomes exchange corresponding DNA segments.

Cell Membrane

A thin, flexible outer barrier surrounding the cell that regulates the entry and exit of substances to maintain internal homeostasis.

Cell Transport

The movement of materials into and out of the cell across the cell membrane.

Passive Transport

The movement of molecules across a cell membrane along a concentration gradient from higher to lower concentration without consuming ATP.

ATP (Adenosine Triphosphate)

The primary energy currency molecule of the cell used to power cellular processes.

Equilibrium

A state in transport where particles are evenly distributed across space and net particle movement stops.

Diffusion

The passive movement of solute particles or gases from an area of higher concentration to an area of lower concentration.

Osmosis

The diffusion of water molecules across a selectively permeable membrane from an area of higher water concentration to lower water concentration.

Facilitated Diffusion

The passive transport of larger or charged molecules across the cell membrane with the aid of specific transport proteins.

Transport Proteins

Membrane-embedded proteins that serve as channels or carriers to assist specific molecules like glucose or ions across the membrane.

Genetic Recombination

The rearrangement of genetic material during meiosis following crossing over that creates new combinations of alleles in gametes.

Recombinant Chromosomes

Chromosomes produced through crossing over that contain a new mixture of maternal and paternal DNA.

Robert Hooke

English scientist who coined the term "cell" in $1665$.

Francesco Redi

Italian scientist who disproved spontaneous generation in $1668$.

Matthias Schleiden

Botanist who stated in $1838$ that all plants are made of cells.

Theodor Schwann

Zoologist who stated in $1839$ that all animals are made of cells.

Rudolf Virchow

Scientist who stated in $1855$ that all cells come from pre-existing cells.

Louis Pasteur

Scientist who performed the swan-neck flask experiment in the $1860\text{s}$ to disprove spontaneous generation and support biogenesis.

Avery, MacLeod & McCarty

Scientists who demonstrated in $1944$ that DNA is the genetic material.

Hershey & Chase

Scientists who confirmed in $1952$ that DNA carries genetic information.

Modern Cell Theory

Theory stating that all living things are composed of one or more cells, the cell is the basic unit of structure and function, all cells arise from pre-existing cells, and energy flow and heredity occur within cells.

Cell Cycle

The orderly, repeating series of events a cell goes through to grow and divide into two identical daughter cells.

Interphase

The longest stage of the cell cycle ($90\%$ of the cycle) where the cell grows, synthesizes proteins and organelles, and copies its DNA without dividing.

G1 Phase

The first growth phase of interphase where the cell grows and makes proteins and organelles.

S Phase (Synthesis)

The stage of interphase where DNA is copied so each chromosome now consists of two sister chromatids.

G2 Phase

The second growth phase of interphase where the cell grows more and completes preparations for division.

M-Phase (Mitosis)

The stage of nuclear division occurring in four steps (prophase, metaphase, anaphase, and telophase) to divide genetic material equally.

Cytokinesis

The splitting of the cytoplasm that completes cell division, forming a cleavage furrow in animal cells or a cell plate in plant cells to produce two separate daughter cells.

G1 Checkpoint

A control point that checks whether the cell is big enough and has undamaged DNA before allowing it to proceed in the cell cycle.

G2 Checkpoint

A control point that verifies whether DNA was copied correctly before cell division occurs.

M Checkpoint

A control point, also known as the spindle checkpoint, that checks if all chromosomes are properly attached before sister chromatids split.

Meiosis

A special type of cell division occurring in reproductive organs that produces four genetically unique haploid daughter cells with half the original chromosome number.

Gamete

A reproductive cell, such as a sperm or egg cell, that contains half the normal number of chromosomes.

Homologous Chromosomes

A pair of chromosomes that carry the same genes but may contain different versions (alleles).

Genetic Variation

Differences in inherited traits and allele combinations among individuals of the same species.

Synapsis

The close pairing of homologous chromosomes during Prophase I of meiosis.

Tetrad

A structure formed during Prophase I composed of two paired homologous chromosomes totaling four chromatids.

Crossing Over

The process occurring in Prophase I where non-sister chromatids of homologous chromosomes exchange DNA segments.

Cell Membrane

A thin, flexible outer covering that surrounds every living cell, regulating the movement of substances entering and leaving.

Cell Transport

The movement of substances into and out of the cell and the exchange of materials between the cell and its surrounding environment.

Passive Transport

The movement of substances across the cell membrane from higher to lower concentration without using cellular energy ($\text{ATP}$).

ATP (Adenosine Triphosphate)

The energy currency of the cell that supplies energy for many cellular activities.

Equilibrium

The state reached when particles are evenly distributed across a space, resulting in no net movement.

Diffusion

The natural spreading of particles from an area of higher concentration to lower concentration until evenly distributed without energy usage.

Osmosis

The diffusion of water molecules across a selectively permeable membrane from an area of higher water concentration to lower water concentration.

Facilitated Diffusion

The passive movement of larger or charged molecules across the cell membrane from higher to lower concentration with the help of transport proteins.

Genetic Recombination

The rearrangement of existing genes during meiosis following crossing over, producing recombinant chromosomes with new allele combinations.

Recombinant Chromosomes

Chromosomes formed after crossing over that contain a mixture of DNA segments and alleles from both homologous chromosomes.