Cell Biology and Genetics 1: Eukaryotic Cells and DNA

Comprehensive vocabulary flashcards covering eukaryotic cell organelles, DNA structure, protein synthesis, and the cell cycle processes of mitosis and meiosis.

Organelles

Membrane bound bodies which all have unique functions, described as "mini organs."

Nucleus

The cell's central organelle which contains the DNA (genetic materials) and serves as the cell's headquarters.

Mitochondria

Bean shaped organelles involved in energy production that create $ATP$ (the energy molecule), originally bacteria with their own genome.

Ribosomes

The site of protein synthesis consisting of two subunits that "read" mRNA and assemble amino acids into tripler codons.

Endoplasmic reticulum (ER)

A large network of folded membranes forming tubes that spread through the cytoplasm and connect to the nuclear envelope.

Smooth ER

Where fatty acids and hormones like oestrogen and testosterone are made; it also controls calcium and detoxifies harmful substances.

Rough ER

ER covered in ribosomes which make proteins for secretion out of the cell and transport to other places in the cell.

Golgi bodies

A stack of membrane-bound sacks called cisterna that make, package, and send cellular products around the cell.

Lysosomes

Small-membrane bound sacs used for recycling and waste control in a process called autophagy.

Plasma membrane

A thin phospholipid bilayer that surrounds eukaryotic cells, containing cholesterol for stability and flexability.

Cytoplasm

The jelly-like guts of the cell which supports the organelles.

Cilia

Hairy-projections anchored below the PM that line airways and move fluids in one direction.

Flagellum

A singular projection that moves in a circular propellor to move the whole cell to a new destination.

DNA

Deoxyribose nucleic acid; the hereditary material composed of repeating units called nucleotides.

Nucleotides

Units of DNA consisting of three parts: a phosphate group, a five carbon sugar, and one of four nitrogenous bases.

Nitrogenous bases

The four types of bases in DNA: adenine ($A$), thymine ($T$), cytosine ($C$), and guanine ($G$).

Pyrimidines

Bases made of one hexagon shaped ring containing four carbon atoms and two nitrogen atoms.

Purines

Bases made of two rings fused together, making them larger than pyrimidines.

Histones

Proteins that DNA wraps itself around to begin the packing process in the nucleus.

Nucleosome

A cluster of $8$ histones.

Chromatin

A flexible protein complex formed by many nucleosomes joined together; it condenses into chromosomes during cell division.

Haploid

One copy of each chromosome ($n$), characteristic of gametes like sperm and egg cells.

Diploid

Two copies of each chromosome; humans are diploid organisms with $23$ pairs ($46$ total chromosomes).

Transcription

The step where DNA is transcribed into RNA by RNA polymerase.

Translation

The process where the mRNA chain is pulled through a ribosome to assemble a string of amino acids called a polypeptide.

Interphase

Occupies $90\%$ of the cell's time; a state where the cell is metabolically active and replicates DNA during the $S$ phase.

$G0$ phase

A non-dividing state outside the active cell cycle where cells perform specialized body functions.

Mitosis

Somatic cell division where one parent cell forms two genetically identical diploid ($2N$) daughter cells.

Prophase

Phase where chromatin condenses into chromosomes, the nuclear envelope dissolves, and the spindle forms.

Metaphase

Phase where chromosomes line up down the middle equator of the cell.

Anaphase

Phase where spindle fibres pull the paired chromatids apart towards opposite poles of the cell.

Telophase

Phase where two new nuclear membranes are built around separated DNA clusters.

Meiosis

A two-step division occurring in gametes that reduces the chromosome count to half (haploid) and produces four genetically unique cells.

Crossing over

The shuffling of genes between homologous chromosomes during meiosis that serves as the basis of genetic diversity.