General Biology: Cell Cycle, Membrane Transport, and Biomolecules

Flashcards covering the cell cycle, mitosis, meiosis, membrane structure/transport, and the Four major biomolecules.

Cell Cycle

The series of stages that a cell goes through as it grows and divides, ensuring proper preparation for division.

Interphase

The longest, non-dividing stage between two successive cell divisions, often described as the 'resting stage' where the cell grows and replicates DNA.

Gap 1 ($G1$) Phase

The period where the cell increases in size, carries out normal functions, and prepares for DNA replication.

Restriction Point

The specific point in the $G1$ phase where a cell becomes committed to division and moves into the $S$ phase.

Synthesis ($S$) Phase

The phase during which genetic material (DNA) and chromosomes are duplicated.

Sister Chromatid

Each individual strand of the double-stranded chromosome produced during the $S$ phase.

Gap 0 ($G0$) Phase

Also called the 'quiescent stage,' where cells are unable to move to $S$ phase and cannot replicate their DNA.

Gap 2 ($G2$) Phase

The phase where the cell synthesizes proteins, continues to increase in size, and prepares for the Mitotic Phase.

Mitosis

The process of nuclear division that produces two identical daughter cells, essential for growth and repair.

Cytokinesis

The division of the cytoplasm that results in two separate daughter cells following telophase.

Karyokinesis

The nuclear division process where 'karyon' refers to the nucleus and 'kinesis' denotes movement.

Histones

Protein spheres around which DNA wraps to stay organized within the cell.

Nucleosome

The single package formed when DNA wraps around histones.

Chromatin

The structural form of DNA where nucleosomes are connected by linker DNA, resembling 'beads on a string'.

Centromere

The region where two identical chromatids are joined to complete a condensed chromosome.

Prophase

The mitotic stage where genetic material resembles polka dots or strings.

Metaphase

The mitotic stage where chromosomes migrate to the middle of the cell.

Anaphase

The mitotic stage where chromosomes move away from each other toward opposite poles.

Telophase

The mitotic stage where the parent cell starts to form two new cells.

Meiosis

A type of cell division that reduces the chromosome number by half, resulting in four genetically unique daughter cells.

Crossing Over (Recombination)

The process in Prophase I where homologous chromosomes exchange genetic material to increase diversity.

Meiosis II

The 'equational' division of meiosis that takes place in haploid cells to pull apart sister chromatids into four unique gametes.

Cell Membrane (Plasma Membrane)

A selectively permeable barrier that encloses the cell and controls the movement of substances in and out.

Fluid Mosaic Model

A model proposed by Seymour Jonathan Singer and Garth L. Nicolson describing the membrane as a flexible layer of lipid and protein components.

Phospholipid Bilayer

The 'fabric' of the membrane composed of hydrophilic phosphate heads and hydrophobic fatty acid tails.

Integral Proteins

Proteins that span across the entire membrane to function as channels or pumps.

Peripheral Proteins

Proteins attached loosely to the interior or exterior surfaces of the membrane, acting as enzymes or structural anchors.

Cholesterol

Steroid molecules that regulate membrane fluidity and prevent phospholipids from packing too tightly at low temperatures.

Diffusion

The passive movement of molecules from an area of high concentration to low concentration.

Facilitated Diffusion

A passive transport process for larger or charged molecules that requires transport proteins like channels or carriers.

Osmosis

The diffusion of water molecules across a selectively permeable membrane from high water concentration to low water concentration.

Isotonic

A solution where solute concentration is equal inside and outside the cell, keeping the cell volume normal.

Hypertonic

A solution with a higher solute concentration outside the cell, causing water to leave and the cell to shrink.

Hypotonic

A solution with a lower solute concentration outside the cell, causing water to enter and the cell to swell.

Active Transport

The movement of molecules against a concentration gradient (low to high) using energy in the form of ATP.

Endocytosis

A process where the cell membrane folds inward to bring large materials into the cell, such as phagocytosis (cell eating) or pinocytosis (cell drinking).

Exocytosis

The process where vesicles fuse with the cell membrane to expel materials like waste or hormones.

Biosynthesis

The process of building organic molecules, also known as biomolecules, by living organisms.

Carbohydrates

Organic molecules with a $1:2:1$ ratio of C, H, and O that serve as the primary energy source.

Glucose

The most common monosaccharide with the chemical formula $C_6H_{12}O_6$.

Starch

A polysaccharide used for energy storage in plants, commonly found in potatoes, pasta, and rice.

Glycogen

A polysaccharide used for energy storage in animals.

Cellulose

A polysaccharide that provides structural support in plant cell walls.

Chitin

A polysaccharide found in the exoskeletons of arthropods and the cell walls of some fungi.

Lipids

Hydrophobic molecules insoluble in water that function in energy storage, membrane structure, and chemical signaling.

Saturated Fats

Fats without double bonded hydrocarbons that are solid at room temperature, such as bacon grease or lard.

Unsaturated Fats

Fats with at least one pair of double or triple bonded carbons that are liquid at room temperature.

Proteins

Complex macromolecules made of amino acids linked by peptide bonds, used for transport, chemical reactions, growth, and repair.

Nucleic Acids

Biomolecules like DNA and RNA that store genetic information and hold instructions to make proteins.

Nucleotide

The monomer of nucleic acids composed of a sugar, a phosphate, and a nitrogenous base (A, G, C, T, or U).