Membrane Transport, Biomolecules, Chromosomes, Protein Synthesis, Cell Metabolism (shortened)

Passive Transport

Movement of molecules across a membrane without energy

Simple Diffusion

Small nonpolar molecules move down their concentration gradient (e.g., O2, CO2)

Facilitated Diffusion

Molecules move through protein channels or carriers down their concentration gradient

Osmosis

the passive movement of water through aquaporins

Active Transport

Movement against concentration gradient, requires ATP

Endocytosis

Cell engulfs large particles by forming vesicles from the membrane

Exocytosis

Cell releases substances by fusing vesicles with the membrane

Diploid Cells

Cells with two copies of each chromosome (46 in humans)

Transcription

Occurs in the nucleus; DNA is used as a template to make complementary mRNA

Translation

Occurs in the cytoplasm on ribosomes; mRNA is read to assemble amino acids into proteins

DNA Role in Protein Synthesis

Stores all instructions to make proteins

mRNA Role

Carries the "recipe" from DNA to ribosome

tRNA Role

Brings the correct amino acids to the ribosome

rRNA Role

Makes up the ribosome and ensures proper assembly of proteins

Metabolism

All chemical reactions necessary to maintain life

Catabolism

Breakdown of substances into simpler molecules

Anabolism

Building larger molecules from smaller ones

Water

Polar molecule, solvent for reactions, regulates temperature, facilitates nutrient

Carbohydrates

Composed of C, H, O; simple (monosaccharides) or complex (polysaccharides); main energy source

Lipids

Hydrophobic molecules (fats

Proteins

Composed of amino acids linked by peptide bonds; enzymes, structural support

Minerals

Inorganic elements needed in trace amounts; bone formation, muscle

ATP

Nucleotide with three phosphate groups; stores and releases energy for cellular processes

DNA

Double helix of nucleotides; stores genetic information and guides protein synthesis

RNA

Single-stranded nucleotides; mRNA carries code, tRNA brings amino acids, rRNA forms ribosomes

Gap Junction

Small protein channels between cells that allow ions and signals to pass directly

Phagocytosis

“Cell eating” – the cell engulfs large particles or microbes into vesicles for digestion.

Pinocytosis

“Cell drinking” – the cell takes in fluid and dissolved solutes in small vesicles.