Lecture 12: A tour of the cell

What is a cell?

The basic structural and functional unit of all life. Organisms can be one cell or trillions of cells.

How many cells does the human body have?

30 trillion cells

Functions of Cells in the Body

protection, repair, digestion, movement and support

Cell Membrane

phospholipid bilayer that contains items within the cell and regulates what enters and leaves the cell

Cytoplasm

The liquid that fills the cell. Important site of many chemical reactions and keeps organelles in suspension.

Neural Cells

cells of neurons that transmit electrical signals

Muscle Cells

cells that contract to cause movement

Skin Cells

cells that keep a watertight barrier between the organism and the outside world.

Sex Cells

cells that pass on genetics to the next generation.

Structural Support Organelles

cytoskeleton, plasma membrane, and cell wall.

Cytoskeleton

A network of fibrous proteins that provides the shape of the cell and holds the organelles in place. Acts as scaffolding for the cell, and a highway for motor proteins to carry material throughout the cell.

Organelle for DNA Containment

Nucleus

Nucleus

A porous organelle that protects and contains DNA. Lets only specific molecules in an out, such as RNA.

Protein production/Processing Organelles

Ribosome, rough ER and Golgi apparatus.

Role of RNA in protein production

RNA carries information to make proteins and is processed by a ribosome.

Ribosome

The ribosome processes RNA and then builds proteins using RNA as a template. Ribosomes can be free-floating or embedded into other organelles, like the rough ER.

Rough Endoplasmic Reticulum (ER)

organelle with embedded ribosomes that facilitates protein folding and packages them for transport. Ribosomes embedded can make proteins directly into the rough ER.

Golgi Apparatus

organelle that modifies proteins and directs proteins to their final destinations. Like a post office of the cell.

First Step to make a protein

RNA codes for protein using the ribosome

Second step to make a protein

then goes into the rough ER and sends the proteins to the golgi apparatus

Third Step to make a protein

Golgi apparatus modifies the protein and directs it to its final destination

Digestion Organelles

lysosomes, peroxisomes

Digestion In the Cell: how does it work?

larger polymers broken down to smaller polymers or monomers, and waste products and toxic chemicals are neutralized.

Peroxisomes

contains hydrogen peroxide and enzymes and is a very common disinfectant.

Function #1 of Peroxisomes

break down long fatty acids.

Function #2 of peroxisomes

free radicals are dangerous to the cells, so peroxisomes use hydrogen peroxide to neutralize the free radicals.

Lysosomes

organelle that contains a high diversity of digestive enzymes. Takes in larger molecules and breaks them down into their monomers. They are highly acidic

organelles of energy production

mitochondria and chloroplasts

Mitochondria

produce ATP for all eukaryotic cells through cell respiration

Chloroplasts

converts sunlight into chemical energy in the form of carbohydrates.