exam practice 1

Cell Theory

1. The cell is the basic unit of life. 2. All living things are made of cells. 3. New cells arise only from pre-existing cells.

Compound Light Microscope

Uses light and lenses; magnification up to ~1000x; can view live specimens.

Transmission Electron Microscope (TEM)

Produces 2D images of thin slices; very high magnification; cannot view live specimens.

Scanning Electron Microscope (SEM)

Produces 3D surface images; very high magnification; cannot view live specimens.

Plasma (cell) membrane / Plasmalemma

Flexible barrier separating intracellular from extracellular fluid; composed of a phospholipid bilayer with proteins.

Integral (transmembrane) proteins

Proteins that span across the membrane; involved in transport, acting as receptors and enzymes.

Peripheral proteins

Proteins attached to the surface inside or outside of the membrane.

Phospholipids

Amphipathic molecules with hydrophilic heads and hydrophobic tails.

Cholesterol

Molecule that stabilizes membrane fluidity.

Cytoplasm

Material found between the plasma membrane and the nucleus.

Cytosol

Gel-like fluid within the cytoplasm containing water, proteins, salts, and sugars.

Organelles

Specialized structures within a cell that perform metabolic functions.

Nucleus

Control center of the cell; contains nucleolus, DNA (chromatin/chromosomes), and genes.

Rough ER

Endoplasmic reticulum responsible for protein production.

Smooth ER

Endoplasmic reticulum involved in lipid production, steroid synthesis, and detoxification.

Golgi Apparatus

Organelle that processes and ships proteins and lipids.

Mitochondria

Powerhouse of the cell; produces ATP through respiration.

Lysosomes

Organelles that digest and recycle waste materials.

Centrioles

Organelles that organize cell division and form cilia/flagella.

Mitosis

Process that produces 2 genetically identical diploid cells (somatic cells).

Interphase

The phase where the cell grows and replicates its DNA and organelles (G1, S, G2 stages).

Prophase

First stage of mitosis where chromatin condenses into chromosomes, the nuclear membrane dissolves, and spindle fibers form.

Metaphase

Stage of mitosis where chromosomes align at the equator of the cell.

Anaphase

Stage of mitosis where centromeres split and chromatids are pulled apart, beginning cytokinesis.

Telophase

Final stage of mitosis where the spindle dissolves and new nuclei form, completing cytokinesis.

Meiosis

Process that produces 4 genetically unique haploid gametes (sperm or egg) from one diploid parent, reducing the chromosome number by half.