Ch 4 Cells

Transcript Ch 4 Cells

Chapter 4 - Cell Structure and Function

The printed out notes are more detailed than these slides, you are expected to read the chapter and your notes - anything is fair game on the test, but the cell chapter is largely review.

Lab: microscopes and membranes Thurs: 10/9

A. The Cell Theory

Every living organism is made of one or more cells

The cell is the basic unit of structure and function.

It is the smallest unit that can perform life functions.

3. All cells arise from pre existing cells.

*Why is the Cell Theory called a Theory and not a Fact?

Cells need a

large surface area to volume ratio

If there a person was at the very center of each house and accidently started a fire, the person in which house would have a better chance of escaping?

Figure 4.3

Early Contributions

Hooke Leeuwenhoek Schleiden Schwann Virchow

http://htwins.net/scale2/

B. ALL CELLS HAVE:

1. Cell Membrane a) Phospholipid Bilayer (double layer) b) Proteins c) Carbohydrates

2. Genetic Material

Cytoplasm (cytosol)

ORGANELLES float within cytoplasm and perform specific functions

Prokaryote Cells

Figure 4.4a

Eukaryotes

Endosymbiosis :

All organelles seem to share many properties with bacteria. Lynn Margulis proposed:

endosymbiosis hypothesis: that ancient colonization of large bacteria (became the eukaryotic cell) engulfed smaller bacteria (became the mitochondria, chloroplast, etc.

) Symbiosis = "living together".

*Mitochondria & Chloroplasts have their own DNA Animation at Microbiological Concepts

https://www.youtube.com/watch?v=3ESXvLHceDc

Endosymbiosis Theory

that ancient colonization of large bacteria (became the eukaryotic cell) engulfed smaller bacteria (became the mitochondria, chloroplast, etc.

)

http://www.youtube.com/watch?v=-FQmAnmLZtE

In your notes: Create a diagram comparing prokaryotic and eukaryotic cells. Include examples of each and anything you can remember When done, use ch 4 to label the pictures on your notes outline handout pg 65 and 68

Prokaryote

No Organelles Simple Mostly single cells Archaea and bacteria both Cells DNA Cytoplasm Plasma Membrane Ribosome Cell wall

Eukaryote

Membrane Bound Organelles Nucleus Complex Specific in function Multicellular Plants, Animals, fungi

Quick Recap.......

1. What are the two main types of cells?

2. Which one is larger? 3. Which one does not have a membrane bound nucleus?

4. What are the three main parts of the cell (that all cells have)?

5. What are the 3 components of the cell theory?

6. What theory best explains how eukaryotes evolved? Label the pictures on the top of your notes outline: use 65, 68-69 to help

Prokaryotic or Eukaryotic? 1 2

1. Has membrane bound organelles 2. Includes plant and animals cells 3. Bacteria

E E E

6. Has no organelles

cell biology is a huge area, and is divided into many branches that biologists specialize in...

1) Oncology 2) Microbiology 3) Genetics 4) Paleobiology 5) Pathology ............to name a few Here's an older video that compares prokaryotes and eukaryotes and discusses how cells evolved, film by the Phoenix Learning Group (17 minutes) And a shorter video on the main parts of The Cell

The Parts of the Cell

Cell Diagram Directions:

You will get a picture of a animal or plant cell, label the cell.

label as many parts as you can remember Then look in your book to label the rest Write a 2-5 word description of the function of each part

• • • • II. Nucleus:

Nucleoplasm

: semifluid matrix

Chromatin

: uncoiled, fluid DNA and proteins

Chromosomes

: coiled, rodlike DNA structures

Gene

: unit of heredity located on DNA • •

Nucleolus

: dark region of chromatin where

rRNA

joins with

proteins

to form ribosomal subunits (parts to make ribosomes)

nuclear envelope

contains things to enter and exit

nuclear pores

for some

III. Endomembrane System:

Includes: a.

Nuclear envelope b.

Membrane of the ER c.

Golgi apparatus d.

Several types of lysosomes

I am a reticulated python. Ask me what I have to do with the endoplasmic reticulum.

A. Nuclear Envelope/ Membrane:

RNA leaves nucleus to instruct production of proteins

B. Endoplasmic Reticulum (endoplasm= "within cytoplasm", reticulum= "little net" --divides cell into compartments --channels molecules through the cell's interior, like a little highway, make vesicles Rough ER --has

ribosomes

--functions in Figure 4.10a

protein

synthesis -- ER transports newly assembled proteins to the

Golgi Apparatus

Smooth ER --no ribosomes --mostly contains enzymes that act in

lipid

hormones like estrogen and testosterone) Vary depending on location synthesis (such as

C. Golgi Apparatus: Delivery System -flattened stacks of membranes -functions in collection,

modifying

packaging

and

distributio

n of molecules made in the cell and used elsewhere unprocessed proteins enter the front end ( cis ) near the ER, and are exported near the cell membrane, at the back end ( trans ) --the folded stacks are called

cisternae

Jobs of the Golgi Apparatus (aka Golgi Complex)

1. separates proteins according to their destinations 2. modifies proteins (adds sugar and makes glycoproteins) 3. packages materials into

vesicles

which are exported outside the cell -

secretion

Lysosomes - Intracellular Digestion Centers

--contain high levels of degrading

enzymes

(to "lyse" means to dissolve) --recycle old and worn out cell parts sac”

apoptosis

"suicide -digest other particles taken in by

phagocytosis

--this "food" is stored in food vacuoles, the lysosomes fuse with the vacuoles and release digestive enzymes

Lysosomes - Intracellular Digestion Centers

TAY-SACHS disease

– What do lysosomes have to do with this deadly disease?

Article and Video on Tay Sachs http://6abc.com/archive/9036458/ https://www.youtube.com/watch?v=RzEpkBU-ITA

Tay-Sachs disease is caused by the absence or significantly reduced level of a enzyme called beta-hexosaminidase (Hex-A). Normally, Hex A is a digestive enzyme that is part of the lysosome. Without the correct amount of the Hex-A enzyme, a fatty substance or lipid called GM2 ganglioside accumulates abnormally in cells, especially in the nerve cells of the brain.

Ribosomes - Sites of Protein Synthesis

-each is composed of two

subunits

, one large and one small -mRNA is "read" by the ribosomes and amino acids are assembled into proteins -ribosomes are manufactured by the nucleolus , assembles by ER --

polyribosomes

– strings of ribosomes in the cytoplasm that work to make a protein

Free vs Bound Ribosome

Free ribosomes: produce proteins that are used by the cell. - ex: for metabolism of food. Bound ribosomes: produce proteins that are transported out of the cell. - ex: for a specific function, such as digestive enzymes and polypeptide hormones.

Mitochondria

--contains its own DNA, support for Endosymbiosis • Theory mitochondria divide before cell division, they are not synthesized like other cell parts --

function:

store energy for cell use. Energy is stored in the form of

ATP

adenosine triphosphate -2 membranes, one smooth outer membrane, and an inner membrane folded into layers called

cristae

--Cristae has two compartments: the

matrix

intermembrane space and the

What happens if your mitochondria don’t work?

Mitochondrial Disease Video Why is mitochondrial disease so devastating to children?

Consider the mitochondria have their own DNA separate from the parental DNA. How could you cure this disease?

https://www.youtube.com/watch?v=6_ylLEhRG30

Focus on Plant Cells

Chloroplasts - Where Photosynthesis Takes Place Plants only

--has its own DNA, like mitochondrion --functions : to convert light energy to

carbohydrates

--carbohydrates then broken down in mitochondria to produce ATP

Parts of chloroplast --

thylakoids

Grana :

are the individual disk shaped compartments stack of thylakoids --

stroma

is the fluid surrounded the thylakoids *Chloroplasts are a type of

plastid Chromoplasts –

red, yellow and orange pigment

Leucoplasts –

colorless (potatoes)

Cytoskeleton- support system a. Microfilaments (

now called

actin filament ) –

occur in bundles, form tracks within the cell for the movement of organelles, used to form

pseudopod

s (ameba) b.

Intermediate filaments

- support membrane, cell to cell junctions c.

Microtubules -

the

spindle

(little pipe) radiate from the

centrosome

during cell division

form

Centrioles

division – used during cell to move and separate chromosomes, only found in animal cell

Cytoskeleton

How do cells maintain their shape?

How do they move?

- pseudopod - cilia - flagella

Pseudopod

– extensions of the cell that allow for movement (ameba), depend on actin filaments

Cilia

( hair ) &

Flagella

--function in movement ( whip ) -- 9 + 2 Arrangement of microtubules http://www.youtube.com/ watch?v=7pR7TNzJ_pA

Hey....remember enzymes?

The Peroxisome

Found in plant and animal cells, this organelle plays a critical role in normal cell functioning. In human cells, peroxisomes house some sixty enzymes, involved in metabolic processes such as bile acid, cholesterol, and plasmalogen biosynthesis, as well as ß-oxidation peroxisome produces hydrogen peroxide as a by-product of its normal function. -To neutralize this potentially toxic compound, a peroxisome imports the hydrogen peroxide metabolizing enzyme

catalase

, from the cytosol of the cell. Catalase converts hydrogen peroxide to water and oxygen

Vacuole

-- mainly storage or specific functions (contractile vacuole, fat vacuole) -- Plant cells have a

CENTRAL VACUOLE

and help to maintain hydrostatic pressure - used for storage

QOD:

1. What does the cell theory state? 2. Explain why cells are so small using the idea surface area- to- volume ratio. 3. Compare and contrast plant and animal cells

use a graphic organizer: (venn, tree map, etc) •Plant Cell •Animal cell •Eukaryote •Plasma Membrane •Nucleus •Ribosome •ER •Mitochondria •Chloroplast •Cell wall •Cytoplasm •Golgi Apparatus •Vacuole •Centrioles •Fern Cells •Muscle Cells •Human Cells

Plant Animal

Tree Map

Double Bubble (like a venn diagram)

vacuole Chloroplast Fern Cell wall

Plant Cell

Eukaryote centrioles Nucleus Mitochondria Cytoplasm Plasma Membrane Ribosome ER lysosome Golgi apparatus

Animal Cell

Muscle cells humans

Plant Cell

vacuole Cell wall Chloroplast Fern

Eukaryote

Nucleus Mitochondria Cytoplasm Plasma Membrane Ribosome ER lysosome Golgi apparatus

Animal Cell

centrioles Muscle cells humans

QOD: Proteins in the Cell

What parts of the cell are involved with protein production and what role does each part play? Most of the Endomembrane: • Nucleolus • Rough ER • Golgi • Vesicles • Free Ribosome

Mini Quiz

1. What part of the cell produces vesicles for export?

2. What part of the cell makes proteins?

3. What part of the cell produces ATP?

4. What part of the cell transports materials throughout the cytoplasm?

5. What part of the cell has a cis and a trans face? https://www.youtube.com/watch?v=1Z9p qST72is&feature=youtu.be

a. ________________ b. ________________ c. _________________ d. _________________ e. _________________ f. __________________ f.

Find the: a. Nucleolus b. Centriole c. Vesicle d. Smooth ER e. Lysosome

Figure 4.7b

What is this structure?

Terms / Concepts for Show, Don't Tell

cell_theory mitochondria chloroplast prokaryote protein_synthesis eukaryote nucleus lysosome ribosome endoplasmic_reticulum cytoskeleton golgi_apparatus enzyme messenger_RNA chromatin phospholipid_bilayer cilia flagella microscope peroxisome

Single Cheek Cell - at different illuminations