chapter 4 notes

Chapter 4 Cell Process And Energy

These are some nasty

cells!

You’re some nasty cells!

Cell Biology 1) All living organisms are composed of cells, from just one to many trillions, whose details usually are visible only through a microscope. As a basis for understanding this concept:

d) Students know that mitochondria liberate energy for the work that cells do and that chloroplasts capture sunlight energy for photosynthesis. e) Students know cells divide to increase their numbers through a process of mitosis, which results in two daughter cells with identical sets of chromosomes. f)Students know that as multicellular organisms develop, their cells differentiate.

Genetics2) A typical cell of any organism contains genetic instructions that specify its traits. Those traits may be modified by environmental influences. As a basis for understanding this concept:

e) Students know DNA (deoxyribonucleic acid) is the genetic material of living organisms and is located in the chromosomes of each cell.

Section 1 Photosynthesis - Sun is the source of energy for most living things- energy is used to carry out cellular function- the process of turning light energy into chemical energy (food) called photosynthesis

This grass is so nice and green

because of photosynthesis

!

I think photosynthesis is cooler than my brother!

Photosynthesis

= process by which a cell captures energy from the sunlight to make food

-plants, algae, and some bacteria can do photosynthesis

-Plants use the energy from the sun to convert carbon dioxide and water into oxygen and sugars (carbohydrates)

-2 stages

-Stage 1 = capturing the energy

-Stage 2 = producing the sugar

http://video.google.com/videoplay?docid=-8139187002927068738&q=photosynthesis&total=317&start=0&num=10&so=0&type=search&plindex=9

Stage 1

-In plants this happens in the green parts = chloroplasts

-Pigments = colored compounds that absorb the light

-Main pigment is chlorophyll

-Chloroplasts can be different colors than green as well

-This powers the second stage of photosynthesis

Stage 2

- use captured energy to produce sugar (food)

- raw materials = water and CO2

- water goes in through the roots

- CO2 through the underside of the leaves = Stomata

Photosynthesis Equation

-Plant cells use some of the energy from photosynthesis for the plant cell functions

-Some used to make more plant cells (more carbohydrates)

-Some stored for later use (ex. Potatoes, carrots, etc)

-Byproduct for plants (waste) is Oxygen (O2)

-All organisms that carry out photosynthesis produce O2

Photosynthesis and Life

-Autotroph = organism that makes it’s own food (photosynthesizers)

-Heterotroph = organisms that can not make their own food – they need energy from plant sugars

-Almost all plants and animals get their energy directly or indirectly from the sun’s energy

Section 2 Respiration

= releasing energy from breaking down food particles (usually glucose)

+ Energy

Play Converting Food To Energy

-2 stages in respiration

-#1 takes place in the cytoplasm by breaking glucose into smaller molecules = small amount of energy released

-#2 takes place in the mitochondria by breaking down the pieces from #1 into even smaller pieces = lots of energy released – requires oxygen – carbon dioxide and water are products along with energy released

Fermentation = requires no oxygen to get energy out of food

-found in deep ocean and mud

-Amount of energy released is much lower during respiration

-Alcoholic Fermentation = occurs in yeast – alcohol is a waste product – also CO2 causes yeast to rise in baking and CO2 bubbles in beer and sparkling wine

Lactic Acid Fermentation = in muscles when you push them harder than you can supply O2 by breathing (ex. Sprinting)

Section 3 Cell Division

Cell Cycle = growth and division of cells – important for replacing old or damaged cells

6 Parts

1 Interphase

2 Prophase

3 Metaphase

4 Anaphase

5 Telophase

6 Cytokinesis

Mitosis

Play Mitosis Video

Interphase for a cell going into mitosis

-Cell grows to mature size

-Makes a copy of DNA – one will go to each daughter cell (the two new cells) – DNA still loose

-Prepares to divide

Mitosis = cell’s nucleus divides into two new nuclei – one copy of DNA to each daughter cell

Loose Chromatin DNA condenses into 1 Chromosome holding two Chromtids at a Centromere

chromosomes

centromere

Sister chromatids

Prophase

-DNA condense to form Chromosomes

-Spindle fibers form

-Nuclear Membrane breaks down

Metaphase

-Chromosomes line up along center of cell (equator)

-Spindle fiber attaches at centromere

Anaphase

-centromeres split and chromatids separate

-Each chromatid goes to separate sides of the cell

Telophase

-New nuclear membranes form

-Cells begin to divide

Cytokinesis

-Cell separates into two new cells

-Plant cell forms a cell plate between the two

-Each daughter cell ends up with same number of chromosomes and about half the organelles & cytoplasm

-Cell Cycle now over

DNA Replication

-happens before mitosis occurs

-Each daughter cell get a copy of DNA

-Looks like a twisted ladder or spiral staircase

-Called a “Double Helix”

-Sides of ladder made of deoxyribose sugar

-Rungs of ladder have nitrogen bases

-Adenine pairs with Thymine

-Guanine pairs with Cytosine

DNA Replication

-two sides unzip

-New nucleotides floating around in the nucleus pair up with each half

-A goes with T and G with C

-Each side makes an exact match of the original DNA

Play RNA saved Video

Cancer

-a disease where the cells grows and divides uncontrollably and damages healthy tissue around it

-More than 100 types of cancer

-Named after where it begins but can spread

-Begins with damaged portion of DNA = mutation

-Mutation causes cell to divide uncontrollably

-Tumor = mass of abnormal cells

-Treatments = surgery, radiation, and/or drug therapy (chemotherapy)

-Treatments also kill healthy cells

- 2/3 of cancer deaths are caused by tobacco use or unhealthy diets

Go to http://www.oralcancerfoundation.org/dental/slide_show.htm

Section 4 Cell Differentiation - Differentiation = process by which cells change in structure and become capable of carrying out specialized functions = cells become different from one another – some will forms groups of similar cells called tissues – tissues come together to form organs

Play Cell Differentiation Video

- plants and animals start off as one cell – through mitosis and differentiation the single cell becomes an organism with specialized structures – plan for which type of cell it will become is encoded in the DNA found in the all the cell nuclei – DNA guides how the cell develops

– differentiation occurs when certain sections of DNA are turned off – guides the development of the cells – once cells differentiate they usually lose their ability to become a different type of cell

– Plant cells differentiate in similar way as animal cells – cells form tissues that form roots, stems and leaves

– stem cells can differentiate throughout life – found throughout the body – respond to certain needs in the body by becoming specialized cells – ex. Red Blood Cells