8.2 Animal Cell Structure

Nucleus

Control center of the cell; stores DNA and directs cell activities.

Nuclear membrane (nuclear envelope)

Double membrane with pores that surrounds the nucleus and controls what enters and leaves.

Nucleolus

Produces rRNA and assembles ribosome subunits.

Chromosomes / Chromatin

DNA and protein; chromatin is uncoiled DNA for use, chromosomes are condensed DNA for cell division.

Ribosomes

Site of protein synthesis; free in cytoplasm or attached to rough ER. (Dots on ER)

Rough endoplasmic reticulum (Rough ER)

Makes and folds proteins for secretion and membranes; covered with ribosomes.

Smooth endoplasmic reticulum (Smooth ER)

Synthesizes lipids and steroids, detoxifies substances, and stores calcium ions.

Mitochondria

Produces ATP through cellular respiration; powerhouse of the cell.

Golgi apparatus

Modifies, sorts, and packages proteins and lipids into vesicles.

Lysosomes

Contain digestive enzymes that break down waste, pathogens, and old organelles.

Vacuoles

Storage structures for water, nutrients, or waste; large central vacuole in plant cells.

Microtubules

Hollow cytoskeletal structures that maintain shape, move organelles, and form spindle fibers.

Microfilaments

Thin cytoskeletal fibers that help with cell movement, shape, and muscle contraction.

Centrioles

Organize microtubules and help form the spindle during cell division (animal cells).

Plasma membrane (cell membrane)

Selectively permeable phospholipid bilayer that controls entry and exit of substances.