Chapter 7Cell Structure and Function (Aligned with 7.1 Intro Sheet and 7.2 Cell Structure Chart)

IMPORTANT: My hope is that you will use this on your computer as a way to ensure that your chart is filled in completely. If you MUST print it out, please make sure you print SIX SLIDES PER PAGE!! Save a tree!!

7-1 Life is Cellular

A. Cells – basic units of structure and function in living things

B. Early scientists that led to the cell theory

Anton van Leeuwenhoek (1600s) – given credit for developing the 1st mini microscope, looked at pond water and made detailed drawings

Robert Hooke – coined the term “cell” when he looked at slices of cork and dead plant cells

Robert Brown (1833) – observed a dark structure near the center of the cell (we now know this is the nucleus)

Matthias Schleiden (1838) – stated all plants are made of cells

Theodore Schwann (1839) – stated all animals are made from cells

Rudolph Virchow (1855) - stated all cells come from the division of preexisting cells

Lorenz Oken – stated all new cells are the result of division of preexisting cells…VIRCHOW STOLE HIS THUNDER

C. Cell Theory

All living things are composed of cells.

Cells are the basic units of structure and function in living things.

All cells come from preexisting cells.

7-2 Cell StructureA. Cellular Control Center

• Nucleus, nucleolus, chromatin/chromosomes, nuclear membrane/pore

B. Organelles that Store, Clean Up and Support

• Vacuoles, vesicles, lysosomes, cytoskeleton (microtubules, microfilaments), centrioles

C. Organelles that Build Proteins

• Ribosomes, endoplasmic reticulum (smooth and rough), golgi apparatus

D. Organelles that Capture and Release Energy

• Chloroplasts, mitochondria

E. Cellular Boundaries

• Cell wall, cell membrane

F. Fluid Portion Outside of Nucleus (Sort of a boundary!)

• cytoplasm

CELLULAR CONTROL CENTER: NUCLEUS

Function: Information center of the

cell Contains DNA (chromatin

vs. chromosomes) Directs cell activities

2 categories of organisms

Prokaryotes – organisms whose cells lack nuclei (i.e. bacteria)

Eukaryotes – organism whose cells contain nuclei

Structure: NUCLEOLUS – a small, darkened region in the

nucleus that is made up of RNA and proteins, this is where ribosomes are made

CHROMOSOMES – large structures formed from DNA that contain the genetic info CHROMATIN – uncondensed DNA found in non-

dividing cells NUCLEAR ENVELOPE – double membrane

around the nucleus that contains pores, allows molecules to move in and out of the nucleus, and protects the nucleus NUCLEAR PORES – allows passage of materials

into or out of nucleus (RNA, ribosomes)

Nucleus

Nucleus

ORGANELLES THAT STORE, CLEAN UP, SUPPORT: VACUOLE

Structure: Large, central structure in plants Many, small, circular structures in animal cells Filled with liquid

Function: Storage of water, salts, proteins,

carbohydrates, waste products Pressure system for plants, prevents wilting Special case: contractile vacuole - prevents

excess water intake, leading to cell-bursting

Store and move materials between cell

organelles and to/from cell surface

ORGANELLES THAT STORE, CLEANUP, SUPPORT: VESICLE

ORGANELLES THAT STORE, CLEAN

UP, SUPPORT: LYSOSOME

Structure: Small, circular structures Found only in animal cells Contain digestive enzymes

Function: Digestion of:

Worn out organellesDebris Large ingested particles

Lysosomes are responsible for your hands not being webbed!!

Lysosome

ORGANELLES THAT STORE, CLEAN UP, SUPPORT: CYTOSKELETON

Structure: Hollow tubes of proteins Examples: cilia, flagella, centrioles

Function: Framework Provide cell with support, structure and shape Movement (cilia, flagella)

Microfilaments - allow movement of cytoplasm within the cell (cytoplasmic streaming)

Microtubules - Maintain cell shape, make up cilia, flagella and centrioles

ORGANELLES THAT STORE, CLEAN UP, SUPPORT: CENTRIOLES

Organize cell division

ORGANELLES THAT STORE, CLEAN UP, SUPPORT: PLASTID

Structure: Differ based on type of plastid (chloroplast is

one example) Found only in plants

Function: Store food/starch Store pigments (give color to fruits & veggies)

ORGANELLES THAT BUILD PROTEINS: RIBOSOMES

Structure: Small (25 nm) ball-like

structures Found free-floating in

cytoplasm or attached to rough endoplasmic reticulum

Composed of RNA and protein

Function: Synthesis of proteins (where

proteins are made)

Structure: Network of flattened sacs Can be rough (w/

ribosomes) or smooth (w/o)

Function: Transport materials within

or out of cell Synthesis of

macromolecules Rough - proteins,

lipids, carbsSmooth - lipids

ORGANELLES THAT BUILD PROTEINS: ENDOPLASMIC RETICULUM

ORGANELLES THAT BUILD PROTEINS: GOLGI APPARATUS

Structure: Flattened stacks of membranes Vesicles attached to top and

bottom

Function: Collection, modification, packaging

of proteins and other substancesVesicles attach, deposit materialsGA modifies materials based on needsVesicles attach to membrane and

distribute modified substances

ORGANELLES THAT CAPTURE/RELEASE ENERGY: CHLOROPLAST

Structure: Double membrane Elaborate structure inside

Function: Another power station Found in plant cells only Conversion of light energy (sun) into

chemical energy (glucose)

ORGANELLES THAT CAPTURE/RELEASE ENERGY:

MITOCHONDRIAStructure:

Double membraneCristae - inner folds, increase

surface areaOuter membrane for protection of

cell

Function: “Powerhouse” of the cell Able to self-replicate ( # in cells

with high energy need) Converts sugars into energy for

cells

CELLULAR BOUNDRIES: CELL WALL

Only in plants, algae, and some bacteria Lies outside the cell membrane Function

Helps to protect and support the cell Very porous (water, oxygen, carbon dioxide, etc. can

pass through easily) Gives rectangular shape to plant cells

Layers 1st layer – contains pectin (gluey substance that

helps hold the cells together) 2nd layer – primary cell wall (made of cellulose) 3rd layer (in woody stems) – secondary cell wall

(composed of cellulose and lignin to make cellulose more rigid)

CELLULAR BOUNDRIES:CELL MEMBRANE – outer boundary

Structure: Phospholipid bilayer

• hydrophilic heads, hydrophobic tails Contains lipids (bilayer), proteins (channels),

and carbohydrate chains (identification cards)

Function: Regulates what enters and leaves the cell Semi-permeable membrane Protection and support

Cell/Plasma Membrane

CELLULAR BOUNDRIES:CYTOPLASM

Material between the cell membrane and the nucleus

Contains the organelles of the cell

QUESTIONS: Describe the steps involved in the synthesis, packaging, and exporting of a protein from

a cell. Proteins assembled on ribosomes (if targeted for export to cm or to

specialized locations w/in cell, complete their assembly on RER protein in vesicle Golgi apparatus (further modifies, proteins before sorting and packaging them in membrane bound vesicles vesicle final destination

What are the two major parts of the cell? Cytoplasm with organelles, and nucleus

How do contractive vacuoles help maintain water balance? Pump out excess water

What is the difference between rough and smooth ER? Rough has ribosomes, smooth does not

Why is the cell membrane sometimes referred to as a fluid mosaic? What part of the cell membrane acts like a fluid? And what makes it like a mosaic? It is made of many parts (like a mosaic) that can float around in the fluid

phospholipid bilayer How do the properties of lipids help explain the structure of the cell membrane?

Hydrophilic lipid heads are attracted to water, hydrophobic fatty acid tails turn away from water. A bilayer forms when heads turn outward towards water inside and outside a cell

Why do you think it’s important that cell membranes are selectively permeable? Allows needed substances to enter and wastes to leave, while keeping

molecules that are not needed out

Plant vs. Animal Cell

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