Cells and Systems

Cell Structures and Functions

BrainstormTake a crack at the guiding questions.

What is a cell? Finish this sentence.

A cell is . . .

the basic unit of life

like a little factory

alive

amazing

very small

The Cell Theory – 3 statements1. All living things are made up of cells

Unicellular organisms are comprised of a single cell. Most bacteria and protists are unicellular

The Cell Theory – 3 statements1. All living things are made up of cells

Multicellular organisms are comprised of many cells.

In simple multicellular organismslike algae, these cells are all similar.

In more complex multicellular organisms, there can be many different types of cells.

The Cell Theory – 3 statements2. Cells are the basic units of structure

and function in organisms.

In unicellular organisms, each individual cell must perform all of the functions required for life.

The Cell Theory – 3 statements2. Cells are the basic units of structure

and function in organisms.

In multicellular organisms, different types of cells work together so overall, the organism can perform the functions required for life.

The Cell Theory – 3 statements3. All cells arise from existing cells.

Cells grow, develop and divide into more new cells.

What is inside a cell? Cells are often classified based on their structure and the organelles found inside. For example

Cells can be classed as either animal or plant cells

Cells can be classed as either prokaryotic or eukaryotic

To understand these classifications, we must first know what structures can be found inside cells and what the purpose of these structures are.

Section 7-2

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Nucleus

Nucleolus

Cell Membrane

Cytoplasm

Structure of Eukaryotic Cellsall eukaryotic cells have the features

shown here using an animal cell as an example

Cell Membrane The outer covering of the cell Function: transportation of nutrients

and waste materials into and out of the cell

the membrane controls what enters and leaves the cell

Cytoplasm The substance that fills the cell Function: holds all the cell structures

(called organelles) except nucleus most cellular processes occur in the

cytoplasm

1. Nucleus Nickname: “The Control Center” Function: holds the DNA Parts:

1. Nucleolus: dark spot in the middle of the nucleus that helps make ribosomes

Section 7-2

Figure 7-5 Plant and Animal Cells

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Nucleus

Nucleolus Ribosomes

Cell Membrane

Cytoplasm

2. Ribosomes Function: makes proteins Found in all cells, prokaryotic and

eukaryotic

Section 7-2

Figure 7-5 Plant and Animal Cells

Go to Section:

Nucleus

Nucleolus

Rough Endoplasmic Reticulum

Smooth Endoplasmic Reticulum

Cell Membrane

Cytoplasm

Ribosomes

3. Endoplasmic Reticulum (ER) Nickname: “Roads” Function: The internal delivery

system of the cell 2 Types:

1. Rough ER: Rough appearance because it has

ribosomes Function: helps make proteins, that’s

why it has ribosomes

2. Smooth ER: NO ribosomes Function: makes fats called lipids

used in cell membrane

Section 7-2

Figure 7-5 Plant and Animal Cells

Go to Section:

Nucleus

Nucleolus

Rough Endoplasmic Reticulum

Smooth Endoplasmic Reticulum

Ribosomes

Golgi Complex

Cell Membrane

Cytoplasm

4. Golgi Complex Nickname: The “shippers” Function: packages, modifies, and

transports materials to different location inside/outside of the cell

Appearance: stack of pancakes

5. Lysosomes: circular, but bigger than ribosomes) – not shown

Nickname: “Clean-up Crews” Function: to break down food into

particles the rest of the cell can use and to destroy old cells

Section 7-2

Figure 7-5 Plant and Animal Cells

Nucleus

Nucleolus

Rough Endoplasmic Reticulum

Smooth Endoplasmic Reticulum

Ribosomes

Golgi Bodies

Mitochondria

Cell Membrane

Cytoplasm

6. Mitochondria Nickname: “The Powerhouse” Function: Energy formation – the

site of cellular respiration Breaks down food to make ATP

ATP: is the major fuel for all cell activities that require energy

Nucleus

Nucleolus

Rough Endoplasmic Reticulum

Smooth Endoplasmic Reticulum

Ribosomes

Golgi Bodies

Mitochondria

Cell Membrane

Cytoplasm

Now let’s talk about structures only found in PLANT Cells!!

Section 7-2

Figure 7-5 Plant and Animal Cells

Go to Section:

Plant Cell

Cell Membrane

Vacuole

7. Vacuoles Function: stores water, supports cell

structure This is what makes lettuce crisp

When there is no water, the plant wilts

Section 7-2

Figure 7-5 Plant and Animal Cells

Go to Section:

Plant Cell

Cell Membrane

Vacuole

Chloroplasts

8. Chloroplasts Function: traps energy from the sun

to produce food for the plant cell through photosynthesis

Green in color because of chlorophyll, which is a green pigment

Section 7-2

Figure 7-5 Plant and Animal Cells

Go to Section:

Plant Cell

Cell Membrane

Vacuole

Chloroplasts

Cell Wall

9. Cell Wall Function: provides support and

protection to the cell membrane Found outside the cell membrane in

plant cells

Plant Cell

Cell Membrane

Vacuole

Chloroplasts

Cell Wall

Nucleolus

Nucleus

Rough ER

Smooth ER

Golgi Bodies

Mitochondria

Ribosomes

Cytoplasm

Comparing Plant and Animal CellsPlant Animal

Eukaryotes and Prokaryotes

All living organisms can be classified as either eukaryotes or prokaryotes depending on the structure of their cells

bacteria

protistsfungiplants animals

protistsfungiplants animals

Prokaryotes and Eukaryotes

no nucleusno membrane bound organellesgenetic material is DNADNA is a single loopmost are unicellular, some multicellularhave ribosomeshave a cell wallno cytoskeletonsmall

Prokaryotes Eukaryotesmembrane bound nucleushas membrane bound organellesgenetic material is DNADNA is organized in chromosomescan be unicellular or multicellularhave ribosomesonly plant cells have cell wallscytoskeletonlarge

Prokaryotes Eukaryotes