Week 3: Organization of the Cell

What is a cell?

An organized unit that can live and reproduce on its own by utilizing energy, raw materials, and DNA instructions.

Define cell theory.

The principles stating that all organisms are made up of cells, the cell is the smallest unit of life, and cells can only arise from pre-existing cells.

Nucleoid

A region in prokaryotic cells that houses DNA, distinct from a membrane-bound nucleus.

What are prokaryotic cells?

Cells that are exclusively unicellular, lack a nucleus, and do not have membrane-bound organelles.

What are eukaryotic cells?

Cells that can exist as unicellular or multicellular organisms and have a membrane-bound nucleus and organelles.

List the four structures common to most cells.

Plasma membrane, DNA, cytoplasm, and ribosomes.

Plasma membrane

The outer layer of all living cells, separating internal and external environments.

What is ribosome responsible for?

The site of protein synthesis in both prokaryotic and eukaryotic cells.

Cytoplasm

The semifluid material found between the nucleus and the cell membrane, containing organelles and other components.

Cytosol

The liquid part of the cytoplasm that surrounds the organelles.

Gamete cells

Sex cells, including sperm in males and ova (eggs) in females.

Somatic cells

All body cells excluding gametes, including red blood cells, epithelial cells, nerve cells, etc.

What does 'Eu' in eukaryotic mean?

It means 'normal' and refers to cells that have a nucleus.

What does 'Pro' in prokaryotic mean?

It means 'before' and refers to cells that lack a true nucleus.

What is the role of the nucleus in eukaryotic cells?

It is the membrane-enclosed organelle that stores DNA.

What is the function of the cytoskeleton?

It provides shape and protection to the cell.

What distinguishes prokaryotic cells from eukaryotic cells?

Prokaryotic cells do not have a nucleus or membrane-bound organelles.

What is the double-membraned structure containing DNA in eukaryotic cells?

The nucleus.

What is the fluid component of cytoplasm that does not include organelles?

Cytosol.