7-1 Life Is Cellular - hcs.stier.org 7 Complete (1)2.pdf · Unlike a cell wall, a cell membrane is composed of a lipid bilayer. provides rigid support for the surrounding cell. allows

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7-1 Life Is Cellular


The Discovery of the Cell

What is the cell theory?


The Discovery of the Cell

The cell theory states:

• All living things are composed of cells.

• Cells are the basic units of structure

and function in living things.

• New cells are produced from existing

cells.


Exploring the Cell

Electron Microscopes

Electron microscopes reveal details 1000 times

smaller than those visible in light microscopes.

Electron microscopy can be used to visualize only

nonliving, preserved cells and tissues.


Exploring the Cell

Transmission electron microscopes (TEMs)

• Used to study cell structures and large protein

molecules

• Specimens must be cut into ultra-thin slices


Prokaryotes and Eukaryotes


Cells come in a variety of shapes and sizes.

All cells:

• are surrounded by a barrier called a cell

membrane.

• at some point contain DNA.



Cells are classified into two categories, depending on

whether they contain a nucleus.

The nucleus is a large membrane-enclosed structure

that contains the cell's genetic material in the form of

DNA.

The nucleus controls many of the cell's activities.



Eukaryotes are cells that contain nuclei.

Prokaryotes are cells that do not contain nuclei.



What are the characteristics of

prokaryotes and eukaryotes?



Prokaryotes

Prokaryotic cells have genetic material

that is not contained in a nucleus.

•Prokaryotes do not have membrane-bound

organelles.

•Prokaryotic cells are generally smaller and

simpler than eukaryotic cells.

•Bacteria are prokaryotes.



Eukaryotes

Eukaryotic cells contain a nucleus in

which their genetic material is separated

from the rest of the cell.



•Eukaryotic cells are generally larger and more

complex than prokaryotic cells.

•Eukaryotic cells generally contain dozens of

structures and internal membranes.

•Many eukaryotic cells are highly specialized.

•Plants, animals, fungi, and protists are

eukaryotes.


7-1

Resources/ch07_sectn01_quiz.qtb


7-1

The cell theory states that new cells are

produced from

a. nonliving material.

b. existing cells.

c. cytoplasm.

d. animals.


7-1

The person who first used the term cell was

a. Matthias Schleiden.

b. Lynn Margulis.

c. Anton van Leeuwenhoek.

d. Robert Hooke.


7-1

Electron microscopes are capable of revealing

more details than light microscopes because

a. electron microscopes can be used with live

organisms.

b. light microscopes cannot be used to

examine thin tissues.

c. the wavelengths of electrons are longer

than those of light.

d. the wavelengths of electrons are shorter

than those of light.


7-1

Which organism listed is a prokaryote?

a. protist

b. bacterium

c. fungus

d. plant


7-1

One way prokaryotes differ from eukaryotes is

that they

a. contain DNA, which carries biological

information.

b. have a surrounding barrier called a cell

membrane.

c. do not have a membrane separating DNA

from the rest of the cell.

d. are usually larger and more complex.

END OF SECTION


7-2 Eukaryotic Cell Structure


Eukaryotic Cell StructuresStructures within a eukaryotic cell that perform

important cellular functions are known as organelles.

Cell biologists divide the eukaryotic cell into two major

parts: the nucleus and the cytoplasm.

The Cytoplasm is the portion of the cell outside the

nucleus.


Plant Cell

Nuclear envelope

Ribosome

(attached)

Rough endoplasmic

reticulum

Cell membrane

Ribosome (free)

Mitochondrion

Golgi

apparatus

Vacuole

Nucleolus

Nucleus

Smooth

endoplasmic

reticulum

Cell wall

Chloroplast

Resources/ActiveArt/index.html


Eukaryotic Cell StructuresSmooth endoplasmic

reticulum

Ribosome (free)

Ribosome (attached)

Golgi apparatus

Mitochondrion

Rough

endoplasmic

reticulum

Cell membrane

Nucleus

Nuclear envelope

Nucleolus

Centrioles

Animal Cell



Nucleus

What is the function of the nucleus?


Nucleus

The nucleus is the control center of the cell.

The nucleus contains nearly all the cell's DNA and

with it the coded instructions for making proteins

and other important molecules.


Nucleus

The Nucleus

Nucleolus Nuclear envelope

Nuclear

pores

Chromatin


Ribosomes

What is the function of the ribosomes?


Ribosomes

One of the most important jobs carried out in the cell

is making proteins.

Proteins are assembled on ribosomes.

Ribosomes are small particles of RNA and protein

found throughout the cytoplasm.


Endoplasmic Reticulum

What is the function of the endoplasmic

reticulum?


Ribosomes

Endoplasmic Reticulum

There are two types of ER—rough and smooth.


Mitochondria and Chloroplasts

What is the function of the mitochondria?


Mitochondrion

Mitochondria

Nearly all eukaryotic cells contain mitochondria.

Mitochondria convert the chemical energy stored in food into compounds that are more convenient for the cell to use.


What is the function of chloroplasts?


Chloroplast

ChloroplastsPlants and some other organisms contain chloroplasts.

Chloroplasts capture energy from sunlight and convert it into chemical energy in a process called photosynthesis.


Cytoskeleton

Centrioles are located near the nucleus and

help to organize cell division.

Cell Organelle Interactive

Plant and Animal Model Interactive

http://www.phschool.com/webcodes10/index.cfm?fuseaction=home.gotoWebCode&wcprefix=cbd&wcsuffix=3072

http://www.phschool.com/webcodes10/index.cfm?fuseaction=home.gotoWebCode&wcprefix=cbp&wcsuffix=3072


7-2



7-2

In the nucleus of a cell, the DNA is usually visible

as

a dense region called the nucleolus.

the nuclear envelope.

granular material called chromatin.

condensed bodies called chloroplasts.


7-2

Two functions of vacuoles are storing materials

and helping to

break down organelles.

assemble proteins.

maintain homeostasis.

make new organelles.


7-2

Chloroplasts are found in the cells of

plants only.

plants and some other organisms.

all eukaryotes.

most prokaryotes.


7-2

Which of the following is NOT a function of the

Golgi apparatus?

synthesize proteins.

modify proteins.

sort proteins.

package proteins.


7-2

Which of the following is a function of the

cytoskeleton?

manufactures new cell organelles

assists in movement of some cells from one place

to another

releases energy in cells

modifies, sorts, and packages proteins

END OF SECTION


7-3 Cell Boundaries

7-3 Cell Boundaries

Why are cells so small?

1. Nutrients must get into the cell and wastes

must be removed;

what limits this exchange is the cell's

surface area-to-volume ratio.

2. Therefore, the smaller the cell the larger

the surface area this means more

materials can be exchanged with the

environment.

By minimizing its size, a cell is maximizing the

speed at which it can communicate, the rate at

which diffusion can occur, and the amount of

surface area at its disposal.

Surface Area/Volume = As Large As Possible

1. 6

2. 3

3. 6

4. 16.6


All cells are surrounded by a thin, flexible

barrier known as the cell membrane.

Many cells also produce a strong supporting

layer around the membrane known as a cell

wall.

Cell Membrane

The cell membrane regulates what enters and leaves the cell and also provides protection and support.


Cell Membrane


Cell Membrane


Cell Walls

What is the main function of the cell wall?


Cell WallCell walls are found in plants, algae, fungi, and many

prokaryotes.


Diffusion Through Cell Boundaries

Measuring Concentration

A solution is a mixture of two or more substances.

The substances dissolved in the solution are called

solutes.

The concentration of a solution is the mass of

solute in a given volume of solution, or

mass/volume.



What happens during diffusion?



Diffusion

Particles in a solution tend to move from an area

where they are more concentrated to an area

where they are less concentrated.

This process is called diffusion.

When the concentration of the solute is the same

throughout a system, the system has reached

equilibrium.


• When equilibrium is reached, solute particles continue

to diffuse across the membrane in both directions.

• Diffusion depends upon random particle movements.

Therefore, substances diffuse across membranes

without requiring the cell to use energy.



Osmosis

What is osmosis?


Osmosis

OsmosisOsmosis is the diffusion of water through a selectively permeable membrane.


How Osmosis Works

Resources/ActiveArt/osmosis_index.html


Water tends to diffuse from a highly

concentrated region to a less concentrated

region.

If you compare two solutions, three terms can

be used to describe the concentrations:

hypertonic (“above strength”).

hypotonic (“below strength”).

isotonic (”same strength”)http://highered.mheducation.com/sites/0072495855/stud

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Osmotic Pressure

Osmosis exerts a pressure known as osmotic

pressure on the hypertonic side of a selectively

permeable membrane.


Facilitated Diffusion

Protein

channel

Glucose

molecules

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http://highered.mheducation.com/sites/0072495855/student_view0/chapter2/animation__how_facilitated_diffusion_works.html


Active Transport

Active TransportSometimes cells move materials in the opposite

direction from which the materials would normally

move—that is against a concentration difference.

This process is known as active transport.

Active transport requires energy.


Active Transport

Molecular Transport

In active transport, small molecules and ions are

carried across membranes by proteins in the

membrane.

Energy use in these systems enables cells to

concentrate substances in a particular location,

even when diffusion might move them in the

opposite direction.


Molecule to be carriedActive

Transport

Molecular Transport

Resources/ActiveArt/active_transoirt_index.html

https://www.youtube.com/watch?v=dPKvHrD1eS4

https://www.youtube.com/watch?v=dPKvHrD1eS4


Endocytosis and Exocytosis

Endocytosis is the process of taking material into the cell.

Two examples of endocytosis are:

phagocytosis

pinocytosis

During exocytosis, materials are forced out of the cell.

https://www.youtube.com/watch?v=pvOz4V699gk

https://www.youtube.com/watch?v=pvOz4V699gk


7-3



7-3

Unlike a cell wall, a cell membrane

is composed of a lipid bilayer.

provides rigid support for the surrounding cell.

allows most small molecules and ions to pass

through easily.

is found only in plants, fungi, algae, and many

prokaryotes.


7-3

The concentration of a solution is defined as the

volume of solute in a given mass of solution.

mass of solute in a given volume of solution.

mass of solution in a given volume of solute.

volume of solution in a given mass of solute.


7-3

If a substance is more highly concentrated outside

the cell than inside the cell and the substance can

move through the cell membrane, the substance

will

move by diffusion from inside the cell to outside.

remain in high concentration outside the cell.

move by diffusion from outside to inside the cell.

cause water to enter the cell by osmosis.


7-3

The movement of materials in a cell against a

concentration difference is called

facilitated diffusion.

active transport.

osmosis.

diffusion.


7-3

The process by which molecules diffuse across a

membrane through protein channels is called

active transport.

endocytosis.

facilitated diffusion.

osmosis.

END OF SECTION

Documents

7-1 Life Is Cellular - hcs.stier.org 7 Complete (1)2.pdf · Unlike a cell wall, a cell membrane is composed of a lipid bilayer. provides rigid support for the surrounding cell. allows