Exchange with the Environment4-1

Every cell has a cell membrane!~ protects ~ helps move things in and out of cell

~ cell memb. controls this by being selectively permeable - only lets certain things in/out

~ is made of lipids (fats) and has proteins in it to allow things in or out

2 types of transport:1.) Passive transport - does not use energy

*all things want to reach and be in equilibrium- when a space is filled evenly

ex:

Diffusion – movement of particles from areas of high concentration to low concentration

Ex:

2.) Active Transport - uses energy

We will talk more about this in a bit...

http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter2/animation__how_diffusion_works.html

Let's see it in action!

Osmosis – movement of water across a selectively permeable membrane in response to a high solute concentration

Ex:

3 conditions of osmosis:Hypertonic solution: more particles outside the cell than inside

Solution is hypertonic

Cell solution is hypotonic

Water moves out of the cell

Cell will shrivel and shrink

Hypotonic solution: more particles inside the cell than outside

Solution is hypotonic

Cell solution is hypertonic

Water moves into the cell

Cell will burst!

Isotonic solution: same solute concentration inside and outside the cell

Solution is Isotonic

Cell solution is Isotonic

Water moves equally into and out of the cell

Cell will stay the same

http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter2/animation__how_osmosis_works.html

Let's see it in action!

solute particle water molecule

2.) Active Transport - uses energy

Vesicles: some substances are too large to go through the membrane

Are brought in or released by these processes...

~ Endocytosis - cell engulfs or "eats" a substance

Let's see how it works!

~ Exocytosis - cell releases a substance out of the cell * hormones, proteins

http://www.college-cram.com/study/biology/cell-membranes/endocytosis/

http://www.college-cram.com/study/biology/cell-membranes/exocytosis/Let's see how it works!

Photosynthesis is how plants obtain energy!~ done by autotrophs

Cell Energy!4-2

Plants take CO2 and H2O and convert it to glucose and O2.

The heterotrophs then take those products (glucose and O2) and use them for energy in cellular respiration

Ex:

chloroplast

photosynthesis

O2 + glucose

ATP

cellular respiration

CO2 + H2O

mitochondria

3 steps:

1.) Plants harvest energy from the sun~ thylakoids – contain chlorophyll - within the chloroplastEx:

Chlorophyll is a pigment that absorbs red and blue but reflects green and yellow

Also have carotenoids – absorb green and bluereflect red, orange and yellow

~ where we get the fall leaf colors!

2.) Light reactions produce energy

3.) Dark reaction produces sugars

~ uses light energy to make some ATP

~ use the ATP from the light reaction to make glucose!

~ "Dark" because it doesn't use light!!

http://www.science.smith.edu/departments/Biology/Bio231/ltrxn.html

Cellular Respiration

Energy that was made in photosynthesis can be used in cellular respiration

Has 2 stages:

1. Glucose converted to pyruvate - produces small amount of ATP*occurs in the cytosol

2. O2 present = pyruvate used to produce lots of ATP : aerobic - needs O2

* occurs in mitochondria (eukaryotic cells); * in cell membrane in cells w/o mitochondria

O2 not present = pyruvate converted to lactic acid or ethyl alcohol ~ anaerobic - w/o O2

Here's how it works:

glucose

pyruvate

ethyl alcohol or

lactic acid

ATP

AnaerobicAerobic

mitochondria

O2 availableO2 NOT available

ATP

Connection between Photosynthesis and Cell Respiration

C6H12O6 + O2 CO2 + H2O + 36ATP

Light + CO2 + H2O C6H12O6 + O2

These are the chemical equations for both processes...notice anything?

Cell Resp.:

Photosynthesis

One cannot be without the other!

They form a continuous cycle!

Without O2, Fermentation occurs! (Just write and know the things in color!)*instead of the e- getting carried away by NAD+, the e- remain attached to NADH*this takes up all available NAD+ and then glycolysis can't

continue

*SO the H+ must be attached to something else…- in animals = H+ gets attached back to pyruvate to

form ... lactic acid *this is what causes your

muscles to hurt when you work out!

- in plants = H+ gets attached to CO2 from glycolysis to form ...

ethyl alcohol *this is what causes bread to rise (CO2) and beer to become alcoholic (ethyl alcohol)

*Yeast is the microorganism that performs this task!

The Cell Cycle4-3

Chromosomes!

Chromosome - rod shaped structure that forms when a single DNA molecule and its associated proteins coil tightly before cell division

*Made up of genes which make up DNA - ~ segment of DNA that carries info from the parent to the offspring

*Usually the DNA strand is uncoiled when in use.*When the cell prepares to divide, the DNA

coils up and compacts for easier division

DNA looks like this:

Chromatid - one of a pair of strands of DNA that make up a chromosome*DNA replicates itself before cell division so each new cell will have the same genes

The chromatids are joined in the center by a centromere made of protein.

They look like this:

centromere

chromatid chromatid

chromosome

We have 23 types of chromosomes! (46 total)

*body cells have 2 of each type of chromosome (diploid)

*the 2 copies of each type are homologous chromosomes

*one copy from Dad, one from Mom

*sex cells (gametes) only have 1 of each type (haploid)

When 2 sex cells join, then the new zygote will have the correct number of chromosomes!

Homologous

FYI:

Chromosomes affect development:*Most babies with less than 46 die before they become a fetus.

* A person can live with more…like 47:~ Down Syndrome = has extra chrom. #21

~ trisomy – extra chromosome in a 2n cell~ can determine this with a karyotype – look at a map of the

chromosomes…

Chrom. # 21 does not separate at time of cell replication = nondisjunctionie: one cell gets both chrom’s and the other gets none.

Mutations – changes in an organism’s genetic material

Sex chromosomes are the only pair the determine whether you’re female or male!

2 forms = X and YThe presence or absence of the Y chromosome is what determines the sex…

this is because the hormone that makes a male is located on the Y

· Without it, the organism is female!

With us… Females = XX Males = XY

Mitosis and the Cell Cycle4-3

Your book says the cell cycle is in 3 stages:

1 - Interphase2 - Mitosis3- Cytokinesis

(Interphase can be broken into 3 phases and Mitosis is really 4 so just FYI ...there are phases within these phases!)

Interphase:

~ this phase is what the cell spends most of its life in

* During this phase the DNA is copied , at end you have a chromosome with 2 chromatids

* When interphase ends, Mitosis now begins (M phase) Here’s what takes place now…

http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter2/animation__how_the_cell_cycle_works.html

Let's see how it works!

Mitosis!

Prophase:

* chrom. begin to condense

* enzymes break down nuclear envelope

* cylindrical centrioles start to separate and move to opposite ends of the cell – called “polar bodies”

* protein fibers from centriole form spindle fibers – made of microtubules

**NOTE! Plants do NOT have centrioles!**

Metaphase:

* chrom. keep condensing

* chrom. line up in the center of the cell – “equator”

* more microtubules extend out of the centromere at the kinetochore – hold the chroms in place

* one chromatid is attached to one centriole, one to the other

Anaphase:

* centromere divides and the 2 chromatids separate

* the new chroms. move to opposite sides as the spindle fibers shorten

Telophase:* chroms uncoil at either end of cell

*new nuclear envelope forms

* spindle fibers break down and disappear

Cytokinesis begins – cell is cleaved in half

* cell membrane grows to close both

* done by a belt of protein threads

In plants… golgi bodies form a cell plate at the center of the cell to build a new cell wall

- once the wall is complete, the cell separates!

SO... The whole Mitosis process is like this:

http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter2/animation__mitosis_and_cytokinesis.html

Let's see it in action!