Cell Structure

BiologyUnit 4 Notes #2

(Sections 3.2 – 3.4)

The genetic material in a prokaryotic cell is not surrounded by a membrane.

Cell Types With more advanced microscopes,

scientists discovered that all cells can be grouped into two types:• prokaryotic cells • eukaryotic cells

Most prokaryotic cells are unicellular organisms (bacteria) called prokaryotes.

Cell Types Plants, animals, fungi, and protists are all

made of eukaryotic cells and are called eukaryotes.

In eukaryotic cells, the genetic material is surrounded by a membrane.

Every eukaryotic cell has membrane-surrounded organelles, which have specialized functions and enable the cell to carry out different functions at the same time.

Review – Cell Types

1) Which category of cells contain nuclei?

2) How do prokaryotes and eukaryotes differ?

All cells take in food, rid waste, reproduce

3 main sections

1) Cell membrane

2) Cytoplasm

3) Nucleus

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Basic Eukaryotic Cell Structure

1. Cell Membrane

Function: Controls the passage of materials into and out of a cell

Double layer of phospholipids (bilayer) Semi-Permeable: only some materials may

enter/exit

Phospholipid Composition

3 PartsPolar Head

1) Phosphate Group 2) Glycerol

Nonpolar Tails 3) Two chains of fatty acids Arrangement:

Outside: Polar heads Inside: Nonpolar Tails

phosphate

glycerol

Fatty acids

1. Cell Membrane

Phospholipid Bilayer

“Water-loving”

“NOT Water-loving”

1. Cell Membrane

Review

1) Name the 3 parts to a phospholipid?2) Which part(s) make up the head of a

phospholipid?3) Which part(s) make up the tails of a

phospholipid?4) Which part of phospholipid always seems to

be in contact with a watery environment? Why?

Jelly-like material inside of the cell

Most organelles float within

Nucleus Ribosomes Vacuoles Mitochondria Chloroplasts ER Golgi Body Lysosomes

Job: Help dissolve solutes & move materials around

2. Cytoplasm

•The cytoskeleton, is found within the cytoplasm maintains the shape of an animal cell.

•The cytoskeleton is a network of threadlike proteins that are joined together.

2. Cytoplasm

The cytoskeleton, maintains the shape of an animal cell.

2. Cytoplasm

3. NucleusIn most cells, the nucleus is the largest organelle. The nucleus is the part of a eukaryotic cell that directs cell activities and contains genetic information stored in DNA.

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DNA in the nucleus is organized into structures called chromosomes.

The nucleolus is also contained in the nucleus and makes ribosomes, organelles involved in the production of proteins.

The nuclear envelope is a porous, two-membrane structure that surrounds the nucleus.

3. Nucleus

Job: Controls cell activity Inside:

1) Chromatin long strands of

DNAholds info to make

proteins

2) Nucleolus: makes ribosomes

3. Nucleus