Cell Functions, Organelles, and Cell Junctions in Human Biology

Epithelial cells

Cover/Line

Hepatocytes

Storage

Adipocytes

Storage

Skeletal muscle cell

Movement

Fibroblasts

Connection

Leukocytes

Defense

Neurons

Communication

Organelle

"little organ"

Nucleus

Harbor/protect DNA (genetic material) and controls protein synthesis.

Chromatin

DNA wrapped around proteins, condenses to chromosomes during mitosis.

nDNA

DNA known as nuclear DNA.

Nuclear pores

Allow certain substances in and out of the nucleus.

Nucleolus

Makes ribosomes.

Ribosomes

Read mRNA codons and facilitate joining of amino acids to build protein.

Mitochondrion

Transforms energy by harvesting energy from glucose and building ATP.

ATP

Used by the cell for energy.

Rough Endoplasmic Reticulum

Attached ribosomes make proteins that may be secreted out of the cell or go into lysosomes.

Smooth Endoplasmic Reticulum

Makes lipids/carbs, detoxifies alcohol and drugs, and stores calcium for muscle cells.

Golgi Apparatus

Tags and modifies proteins for transport outside of the cell, into the cell membrane, or into lysosomes.

Lysosomes

Carries digestive enzymes to digest ingested materials, old organelles, and the cell itself (apoptosis).

I-cell disease

Condition where contents of lysosomes are released into the extracellular environment.

Peroxisomes

Break down hydrogen peroxide using enzymes like catalase.

Cytoskeleton

Provides structure and movement, analogous to musculoskeletal system in the body.

Tight Junctions

No space between cells; substances must diffuse through cells.

Desmosomes

There is space between cells; provides strength.

Gap Junctions

Passageways between cells that allow solutes to travel for cell-cell communication.

Necrosis

Cell damage leads to death, spills cell contents, and causes immune response.

Apoptosis

Organized cell death in response to virus/cancer without spillage or immune response.