Cell Structure and Function

Cell Theory

All organisms consist of cells

The cell is the basic unit of structure for all organisms

All cells arise from preexisting cells

Micrometer

unit of measurement for cells

Nanometers

unit of measurement for subcellular structures and molecules

Angstrom (Å)

0.1 nm

Limit of resolution

how far apart objects must be to appear as distinct

Resolving Power

ability to see fine details

Categories of proteins

Enzymes

Structural proteins

Motility proteins

Regulatory proteins

Transport proteins

Signaling proteins

Receptor proteins

Defensive proteins

Storage proteins

Disulfide bonds

covalent bonds formed between cysteine amino acids

Intramolecular disulfide bonds

bonds that form between cysteines in the SAME polypeptide

Intermolecular disulfide bonds

bonds that for between cysteines in DIFFERENT polypeptides

Primary structure

amino acid sequence

Secondary structure

local folding of the polypeptide that results from hydrogen bonding

Motifs

units of secondary structure consisting of short stretches of alpha helices and beta sheets

Tertiary structure

3D conformation, the hydrogen bonding is maximized in the overall fold of the protein

Quaternary structure

interactions between monomeric proteins to form multimeric units, the level of organization concerned with subunit interactions and assemby

Monomeric proteins

proteins that consist of a single polypeptide

Multimeric proteins

proteins that consist of two or more polypeptides

RNA

contains five-carbon sugar, responsible for information transmission

DNA

deoxyribose, has genetic information

Types of nucleotides

Adenine

Guanine

Thymine

Uracil

Cytosine

Antonie van Leeuwenhoek

the first person to observe living cells

Enzymes

serve as catalysts of chemical reactions in the body

Structural proteins

provide physical support and shape to cells and organelles

Motility proteins

play key roles in the contraction and movement of cells and intracellular materials

Regulatory proteins

responsible for control and coordination of cellular functions

Transport proteins

involved in he movement of other substances into, out of, and within the cell

Signaling proteins

mediate communication between cells in an organism

Receptor proteins

enable cells to respond to chemical stimuli from their environment

Defensive proteins

provide protection against disease

Storage proteins

serve as reservoirs of amino acids

Structure of an amino acid

carboxyl group, amino group, hydrogen atom, R group, and alpha carbon

Condensation reaction

the process of stringing individual amino acids together into a linear polymer by adding each new amino acid to the growing chain

Peptide bond

a C—N bond linking two amino acids