CELL STRUCTURE &

FUNCTION

Ch. 7, Sec. 1-2

Pages 169-181

Section 7.1, Life is CellularI. Discovery of the Cell

A. Robert Hooke, 1665

- First to use a Compound Microscope to look at “cells.”

1. A compound microscope has two lenses. (Objective lens & Eyepiece)

2. Looked at a thin slice of cork which had many “little rooms.”

B. Anton van Leeuwenhoek, 1674

– Used a simple microscope

(one lens) to look at pond water.

– He saw tiny living organism which he called “animalcules.”

II. The Cell TheoryA. What is a cell?

- The basic unit of life.

B. Schleiden & Schwann

– German scientists who stated the cell theory:

1. All living things are made of cells.

2. Cells are the basic units of structure & function.

3. All cells are produced by existing cells.

III. Viewing Cells Close UpA. T.E.M (Transmission Electron Microscope)

– Using a beam of electrons to view the inside of cells & proteins.

– Can only penetrate thinly sliced specimens.

B. S.E.M (Scanning Electron Microscope)

- Produces 3-D images of the outside

structure of cells.

IV. Prokaryotes and EukaryotesA. Prokaryotic Cells

– Cells that do not contain a nucleus.

– DNA is free to float inside the cell.

– All bacteria are an example of prokaryotes.

B. Eukaryotic Cells

- Larger & more complex

- Have a nucleus that contains the DNA

- Have many “specialized” internal structures contained within a membrane (Organelles)

- May live as single cells or make up

multicellular organisms.

- The kingdoms - animals, plants, fungi, and protists are all eukaryotes

Section 7.2 Eukaryotic Cell Structure

I. Types of Eukaryotes.

- Plant, Animal, Fungus

& protist cells

II. Organelles- Membrane-bound structures that act like

individual organs.- Each carries out a specific function.

Cytoplasm

- Area between the nucleus and cell membrane.

- Contains a fluid/jelly-like substance and cytoskeleton

- allows easy movement of wastes and raw materials in and out of the cell

- provides place for chemical reactions

Parts of a Eukaryotic CellNucleus

1. Contains all the DNA within a cell, which it is referred to as the control center of the cell

2. Surrounded by the “Nuclear Envelope.”

- - Membrane that protects the

inside contents and also

allows for the passage of

materials in and out of the

nucleus such as RNA and ribosomes. Movement

of materials is through pores.

Cell BarriersA. Cell Membrane

- Found in all living things prokaryote and eukaryote.

- Is a semipermeable lipid bilayer.

- It is a boundary that controls what goes in and out of a cell.

B. Cell Wall

- Found in plants, algae, fungi & bacteria.

- Provides support and protection to the cell.

- Made mostly of the Carb. Cellulose.

Cell Membrane Structure

Cell Wall

Nucleolus- Located in the center region of the nucleus

and it begins to produce ribosomes.

Chromatin- the form DNA is in when a cell is not

dividing. (which is most of the time!) - DNA wrapped around DNA.

- Looks like tangled spaghetti Chromosomes

- the form DNA is in when a cell is dividing.- Condensed chromatin – looks like X’s

Ribosomes

1. Small grain-like particles of RNA inside the cytoplasm or on the Endoplasmic Reticulum

2. Located throughout the cell

3. Produce proteins from information within DNA.

Endoplasmic Reticulum

1. System of passageways that transports proteins & other materials throughout the cell.

2. Two types of E.R.

a. Rough E.R.

- Is covered with ribosomes which produce proteins.

b. Smooth E.R.

- Mainly responsible for making membrane lipids and breaking down

drugs.

Golgi Body (Golgi Apparatus)

1. Proteins from the E.R. are transported here next.

2. Modifies, or packages proteins and other materials before they are secreted outside

of the cell.

- Puts the “finishing touches” on proteins . proteins.

Lysosomes

1.Small organelles filled with digestive enzymes.

- Break down food molecules that can be used by the cell as well as waste products.

Vacuoles

1. Sac-like structures that store water, food and/or waste products.

- Extremely important in water storage for

plants.

Very large in

Plants

Mitochondria

1. Organelles that convert chemical energy stored in food particles into a more

useful form.

2. Are enclosed by two membranes:

a. Outer- Protects the inside of the

mitochondria and allows materials to

move in and out.

b. Inner- Inside membrane where energy production occurs (ATP).

Chloroplasts

1. Found only in plant cells.

- Capture energy from sunlight and convert

it into chemical energy in the process

known as “PHOTOSYNTHESIS!”

a. Creates “glucose.”

Centrioles – Organelles found in animal cells that help the chromosomes divide during cell division

Cell BoundariesChapter 7.3

I. Cell Membranea. Membrane that surrounds the cell and

regulates what enters and leaves the cell as well as protects and supports the cells.

b. Found in all cells.

c. Comprised of a “lipid bilayer.”

1. Provides a flexible, but strong barrier between the outside & inside of the cell.

d. Contains a variety of proteins (transport) and carbohydrates (communication), all of which perform a specific function for the cell.

Cell Membrane Diagram:

II. Cell Wall

a. Present in all plants, and in a variety of algae, fungi & bacteria.

b. Provides “strong support & protection” for the cell.

c. Plant cell walls are mainly comprised of cellulose.

III. Diffusion & Osmosis1. Concentration

- Refers to the amount of a solute within a solution.a. Solute – substance that is

dissolved in a solution.b. Solution – mixture of two or more

substances that are evenly distributed.

c. Solvent – what the solute is dissolved into- The concentration of a solute in solution can be

critical for proper bodily function.Ex. Sugar in blood versus Insulin levels.

2. Diffusion- Particles moving from an area of high concentration to low concentration. (Cross other things out so your notes read this!)

a. Equilibrium – When the

concentration of solute is the same throughout the solution.

Factors that affect the rate of diffusion:

a. Size of the Concentration Gradient.(how concentrated the sides are)

b. Amount of surface area/ volume

c. When equilibrium is reached(equal concentration on both sides)

d. Temperature

e. Charge of particle

3. Osmosis

- Diffusion of water across a “selectively permeable” cell membrane.

- “Selectively Permeable” refers to how cell membranes will sometimes not allow solute to pass through but will freely allow water to pass through.

Click image for video link!

Types of Osmotic Balance:1. Isotonic Solution

- When solute & water are at equal concentrations on both sides of membrane2. Hypertonic Solution

- When the solution a cell is in has “more solute” than water.

(Cell will shrink by losing water!)3. Hypotonic Solution

- When the solution a cell is in has “less solute” than water.

(Cell will enlarge by gaining water!)When doing osmosis problems, know the solution,

then think of where the water will go to reach equal water concentrations on each side (water is the only thing that can move)

Two Types of Transport: (this say diffusion in your notes, change to transport)

1. Passive Transport

- When particles move from high concentration to low concentration without the use of energy.

Click image for video link!

Two Types of Passive Transport:

A. Simple Diffusion

- When particles move directly through the lipid bilayer.

Examples: Oxygen & Carbon Dioxide & Water

B. Facilitated Diffusion

- Particles cannot pass through bilayer.

- Pass through transport proteins due to their size or charge.

Examples: H+ ions and GlucoseClick image for video link!

2. Active Transport

- Movement of substances against their concentration gradient (Low to High).

- Requires energy (ATP) & transport proteins to occur.

Click image for video link!

Endocytosis

• Type of Active transport

• The process of taking material into the cell by means of infoldings, or pockets of the cell membrane

Endocytosis• 2 types of Endocytosis:• Phagocytosis – Extensions of cytoplasm

surround a particle and package it within a food vacuole – amoebas

• Pinocytosis – cells taking in liquid into vesicles

Exocytosis

• Also active transport

• The process of cells releasing large amounts of material