Biology Basics

Study Notes

Cells are the basic units of life, with two main types: prokaryotic (bacteria) and eukaryotic (all other living things)
Prokaryotic cells lack membrane-bound organelles, have a single circular DNA molecule, and free ribosomes and a cell wall
Eukaryotic cells have membrane-bound organelles, multiple linear DNA molecules, and histones on DNA

Nucleus: holds DNA and nucleolus, where ribosomal subunits are made
Mitochondria: double membrane, site of cellular respiration, outer membrane is smooth, and inner membrane is folded with enzymes
Ribosome: site of translation, protein synthesis, made of rRNA and protein
Endoplasmic Reticulum (ER): connected to nucleus, allows for reactions, membranous, smooth ER for lipids, and rough ER for proteins
Golgi Complex: packaging in membrane and signals for export
Cytoskeleton: microfilaments, microtubules, and centrioles; gives shape, movement, and support to the cell
Vacuoles/Vesicles: storage of water and solutes

Phospholipid bilayer: selectively permeable, amphipathic
Fluid Mosaic Model: in motion, proteins, cholesterol, glycoproteins, and glycolipids among phospholipids
Types of transport: simple diffusion, facilitated diffusion, active transport, endocytosis, and exocytosis
Osmosis: diffusion of water using a selectively permeable membrane

Energy: free energy is used for organization, growth, and reproduction
First law of thermodynamics: energy is not created or destroyed, only converted
Second law of thermodynamics: entropy increases, organization decreases
Cellular Respiration: breaks down glucose, produces ATP, occurs in mitochondria, and involves glycolysis, Krebs cycle, and electron transport chain
Photosynthesis: captures free energy, uses water and carbon dioxide, produces glucose and oxygen, and occurs in chloroplasts

Cell cycle: interphase, cell division, and cytokinesis
Interphase: growth, synthesis of DNA, and preparation for mitosis
Mitosis: duplicated chromosomes line up, spindle fibers pull them apart, and cytokinesis divides cytoplasm and reforms cell membrane
Checkpoints: internal controls, external signals, and DNA damage

DNA structure: double helix, nucleotides, phosphate, sugar, nitrogen base, and antiparallel strands
DNA replication: semi-conservative, bidirectional, and involves helicase, DNA polymerase, and ligase
RNA: single stranded, ribose sugar, uracil instead of thymine, and base pair rules
Transcription: making mRNA, involves RNA polymerase, and occurs in the nucleus
mRNA editing: introns are excised, exons are spliced together, and a polyA tail and GTP cap are added
Translation: mRNA code is read, matched with tRNA, and constructs a polypeptide using the ribosome

Any change in the DNA sequence, can be inheritable if in egg or sperm
Point mutations: one nucleotide error, substitutions, insertions, or deletions
Frame shift mutations: one or more bases deleted or inserted
Silent mutations: substitution codes for the same amino acid or deletion/insertion is of three nucleotides