Ch. 4 Cell Structure and Function

Ch. 4 Cell Structure and Function

Intro.-4.2

What are the 7 Characteristics of Life?

Intro.-4.2

What are the 7 Characteristics of Life?

Cells, organization, reproduction, energy use, response to stimuli, adaptation, growth

Cells, organization, reproduction, energy use, response to stimuli, adaptation, growth

I. Cell Discovery Timeline:

Early 17th centuryEarly 17th century

Galileo Galilei-among the first

to record a biological observation made with a “microscope”

Galileo Galilei-among the first

to record a biological observation made with a “microscope”

mid 17th centurymid 17th century

Robert Hooke-coined the term

“cell” after observing dead cork cells

Robert Hooke-coined the term

“cell” after observing dead cork cells

Late 1600sLate 1600s

Antony van Leeuwenhoek

-observed “animalcules”

=small moving creatures

Antony van Leeuwenhoek

-observed “animalcules”

=small moving creatures

1820s1820s

Robert Brown-with

improvements in lenses, viewed a nucleus

Robert Brown-with

improvements in lenses, viewed a nucleus

18381838

Matthias Schleiden

-hypothesized: each cell must develop independently

Matthias Schleiden

-hypothesized: each cell must develop independently

18391839

Theodor Schwann-animals and

plants are made of cells which have an individual life of their own

Theodor Schwann-animals and

plants are made of cells which have an individual life of their own

mid-19th centurymid-19th century

Rudolf Virchow-every cell comes

from an existing cell

Rudolf Virchow-every cell comes

from an existing cell

II. The Cell TheoryII. The Cell Theory

1. Every organism is composed of one or more cells.

2. The cell is the smallest unit having the properties of life.

3. The continuity of life arises directly from the growth and division of single cells.

1. Every organism is composed of one or more cells.

2. The cell is the smallest unit having the properties of life.

3. The continuity of life arises directly from the growth and division of single cells.

4.1 Basic Aspects of Cell Structure

4.1 Basic Aspects of Cell Structure

Cell- the smallest unit having the properties of life

Cell- the smallest unit having the properties of life

I. Structural Organization of Cells

I. Structural Organization of Cells

Plasma membrane (aka cell membrane)Plasma membrane

(aka cell membrane)-separates the cell

from its environment, allowing substances and signals to move across in controlled ways.

*Found in all cells

-separates the cell from its environment, allowing substances and signals to move across in controlled ways.

*Found in all cells

Nucleus or nucleoid-location of DNA

Nucleus or nucleoid-location of DNA

*eukaryotic cell*eukaryotic cell *prokaryotic cell

CytoplasmCytoplasm

-semi-fluid substance in the cell

-semi-fluid substance in the cell

Prokaryotic cellsProkaryotic cells

-lack a membrane-bound nucleus and organelles

-Kingdoms: ArchaebacteriaEubacteria

-lack a membrane-bound nucleus and organelles

-Kingdoms: ArchaebacteriaEubacteria

Eukaryotic cellsEukaryotic cells

-have a membrane-bound nucleus and organelles

Kingdoms:Protista, Fungi, Plantae, Animalia

-have a membrane-bound nucleus and organelles

Kingdoms:Protista, Fungi, Plantae, Animalia

What 3 parts do all cells have?

What 3 parts do all cells have?

II. Lipid Bi-layer of Cell Membrane

II. Lipid Bi-layer of Cell Membrane

Includes proteins embedded in the membrane which:

1. Act as passive channels for water-soluble substances

2. Pump substances across the bi-layer3. Act as receptors for hormones and

other signaling molecules

Includes proteins embedded in the membrane which:

1. Act as passive channels for water-soluble substances

2. Pump substances across the bi-layer3. Act as receptors for hormones and

other signaling molecules

Read pp. 46-49 in Holt Biology book (lion on

cover)

Read pp. 46-49 in Holt Biology book (lion on

cover)

III. Cell size and shapeIII. Cell size and shape

Cell size is limited by the surface to volume ratio. If a cell expands in diameter during growth, its volume will increase more rapidly than its surface area. Each unit of the cell’s plasma membrane will have to serve much more cytoplasm making cell transport inefficient. Also, a small cell has more efficient transport within the cell from organelle to organelle.

Cell size is limited by the surface to volume ratio. If a cell expands in diameter during growth, its volume will increase more rapidly than its surface area. Each unit of the cell’s plasma membrane will have to serve much more cytoplasm making cell transport inefficient. Also, a small cell has more efficient transport within the cell from organelle to organelle.

On the next slide you will see: Largest human cell by volume Smallest human cell Longest human cell

On the next slide you will see: Largest human cell by volume Smallest human cell Longest human cell

4.2 Microscopes4.2 Microscopes

Micrograph- a photographic image taken through a microscope

Micrograph- a photographic image taken through a microscope

I. Light microscopeI. Light microscope

A. Compound light -light must pass through the specimen-ours magnify 1,000X max.

A. Compound light -light must pass through the specimen-ours magnify 1,000X max.

B. Stereoscope (aka dissecting microscope)

- object is lit from the top and bottom, so can be opaque, 50X

B. Stereoscope (aka dissecting microscope)

- object is lit from the top and bottom, so can be opaque, 50X

II. Electron MicroscopesII. Electron Microscopes

A. Transmission electron microscope- cannot view living organisms, specimens must be sliced and stained

-50- 1,000,000X

A. Transmission electron microscope- cannot view living organisms, specimens must be sliced and stained

-50- 1,000,000X

B. Scanning electron microscope- specimens coated with a thin layer of metal, cannot view living, 3-D

-5-500,000X

B. Scanning electron microscope- specimens coated with a thin layer of metal, cannot view living, 3-D

-5-500,000X

C. Scanning tunneling microscope- scans the surface of the object, can view living

-up to 100,000,000X

C. Scanning tunneling microscope- scans the surface of the object, can view living

-up to 100,000,000X

Why are microscopes a critical discovery?

Why are microscopes a critical discovery?