Cytology

The study of cells.

History of CytologyRobert Hooke

1665Anton van

Leeuwenhoek1674

Matthias Schleiden

1838

Theodor Schwann

1839

Observed cork slice under

microscope. Coined the word

“cell”.

Observed tiny living organisms in drops of pond

water through his simple

microscope.

First to state that all plants are made of cells.

First to state that all animals are made of cells.

The Cell Theory

1) All living things are made of cells.

2) Cells carry out the functions of living things.

3) Cells come from pre-existing cells.

Organization of Cells

Unicellular

• Entire organism is made of one cell

Multicellular

• Organism is made up of many cells.

Organization of cells

Colony

• group of cells living together

Tissue

• A group of cells working together.

Organization of Cells

Organ

• group of tissues working together.

Organ System

• group of organs working together.

Prokaryotic vs. Eukaryotic

Prokaryotic• Cell that does not have a true

nucleus.– Genetic material is not contained in

a nucleus

• Cell wall• No mitochondria• Mesosome• Plasmid• Cells are very small• Ribosomes present

• Ex: Bacteria

Eukaryotic• Cell that has a nucleus.

– Genetic material is separated from the rest of the cell

• May or may not have a cell wall

• Mitochondria provide energy• Cells are larger• Ribosomes present

• Ex: Plant, fungus and animal cells

Prokaryotic vs Eukaryotic

Prokaryotic Eukaryotic

Cytoplasm

• All of the material inside of the cell except the nucleus.

Nucleus

• The control center of a cell. The nucleus contains the cell’s DNA, and is usually the largest object in the cell.– DNA – genetic code

Nucleoulus

• Dark areas in the nucleus where ribosomes are being made.

Ribosomes

• Two part structure that contains RNA. Makes cell proteins.– Proteins are used to make cell parts, or as

enzymes.

Endoplasmic Reticulum

• System of tubes that manufacture and carry materials throughout the cell.– Smooth ER – no ribosomes– Rough ER - ribosomes

Golgi Apparatus

• Packaging system of the cell. Made up of phospholipid bilayer.

Lysosomes

• The destruction crew of a cell. • Contain enzymes, which are released to digest

old cell parts.• If all lysosomes break open at once the cell

dies.– apoptosis – cell death

Vacuoles

• Storage bubble made of piece of phospholipid bilayer from the cell membrane or the Golgi apparatus.

Mitochondria

• The powerhouse of the cell. Carries out cellular respiration.

Choloroplast

• Phospholipid bubble that contains chlorophyll.

• Function is to carry out photosynthesis.– Chlorophyll converts sunlight into glucose, which

the plant stores until needed

Cytoskeleton

• A 3-D support system made of protein fibers (actin and myosin). Below, the yellow strands are the protein fibers making up the cytoskeletons in some cow cells.

Cell Membrane

• Also called Plasma Membrane• Phospholipid bilayer ~ Two layers of lipid

(fat) molecules that form the cell membrane–Hydrophyllic – “water loving”–Hydrophobic – “water fearing”

Cell Membrane

• Proteins ~ Found embedded in phospholipid bilayer. Function in transporting substances across the cell membrane. Also used for identification of substances.

• Carbohydrates ~ Attached to the outer cell membrane. “Stickiness” helps cells hold on to each other and to grab materials from the environment.

Cell Membrane

Cell Wall

• Plant cell walls are made of cellulose (a starch that makes raw vegetables crunchy)

Plant Cell vs. Animal Cell

Plant Cell• Has cell walls• Has chloroplasts• Has a large central vacuole

Animal Cell• Does not have cell walls;

instead has only a cell membrane

• Does not have chloroplasts• Many small, scattered

vacuoles.

Plant Cell (pg. 175 in your textbook)

Animal Cell (pg. 175 in your textbook)

Cell Organelle Foldable• Hold the construction paper in landscape format. • Fold the paper in half.• Open flat and then fold each side toward the center fold.• Title the left column “Animal Cell” and the right column “Plant Cell”.• Write the names of the cell parts found in an animal cell on the front

side of the “Animal Cell” column.• Write the names of the cell parts found in a plant cell on the front side of

the “Plant Cell” column.• Using a pair of scissors, cut under each term until you get to the fold.

This creates tabs. Do this for both columns. See Figure 1, however your columns will have more tabs than the one shown.

• Flip the tabs open and write a description of the term in your own words. Diagrams/pictures should be included.

• You may use the internet to help you with you pictures/diagrams

See wiki for a list of possible projects. You must do 40 points worth of work

Cell Projects