Cells1.Properties of water

Importance of being polar and non-polar

2.Prokaryotic and Eukaryotic Cells

3. How big are cells?

4. Eukaryotic cells

Differences between plant and animal cells

5. The parts of the cell

Plasma membrane

Organelles

• Function of each organelle

6. Cell diagrams

The Properties of Water (32-34)

The Properties of Water Water is a polar molecule:

Oxygen side is slightly negative

Hydrogen side is slightly positive

When molecules have no charges, they are nonpolar

Figure 2.4

What Does Life Require?The Properties of Water Hydrogen bond: the weak attraction between

the hydrogen atom of one water molecule and the oxygen atom of another

Water molecules tend to stick together:

cohesion

Water is a good solvent (p33,34)

The Properties of Water

Water can dissolve salts (ionically bonded compounds) and hydrophilic (water–loving) molecules because both the water and these molecules are polar.

Figure 2.6

Water is a polar solvent

The Properties of Water Non-polar molecules, such as oil, do not

contain charged atoms.

These atoms are called hydrophobic (water–hating).

Just as non-polar molecules do not mix with polar solvents, polar molecules cannot dissolve in non-polar solvents•Water is not the only solvent!

PhospholipidsType of lipid similar to a fat but with only 2 fatty

acid tails and phosphate “head”

The phosphate head is hydrophillic

The fatty acid tails are hyrophobic

Phospholipids Due to the properties of phospholipids, when exposed to water they organize themselves into a bi-layer.

Heads on the outside next to the water

Tails inside away from the water

But the edges are also exposed to water prompting the formation of a sphere.

Plasma membrane

Where there is water, the phospholipids line up so that the head (hydrophilic) is next to the water and the tail (hydrophobic) is away from the water.

Because there is water on both sides you get 2 layers.

Plasma membrane (p44,45) Plasma membrane Also called a lipid bilayer

because it is comprised of 2 layers of lipids

Also- Proteins

- Cholesterol

STUDY GUIDEKnow what kind of molecules will be dissolved in water and which will not and why.

Understand how the properties of phospholipids cause them to form the plasma membrane

Q1. What kind of solvent is water?

Q2. What kind of molecules can water dissolve?

- 3 terms

Q3. What kind of molecules can watter not dissolve

- 3 terms

Q4. Describe the properties of the head group of a phospholipid

Q5. Describe the properties of the tails of a phospholipid

Q6. What happens when you put phospholipids in water?

- what is formed?

- why?

Measurements (nib)

1 meter = 3.28 feet

100 centimeters = 1 meter (cent means 1/100)

10 millimeter = 1 centimeters (milli means 1/1000)

1000 micrometers = 1 centimeter (micro means 1/1,000,000)

1000 nanometers = 1 micrometer (nano means 1/1,000,000,000)

Angstrom 10-10 meters

Picometer 10-12 meters

The scale of things

http://learn.genetics.utah.edu/content/begin/cells/scale/

How many atoms?

How many atoms in a grain of salt?

a grain of salt contains about 1.2x1018 atoms, half of which are sodium atoms. (The other half is chlorine atoms, of course.)

1,200,000,000,000,000,000

1,000 one thousand (3 zeros)

1,000,000 one million (6 zeros)

1,000,000,000 one billion (9 zeros)

1,000,000,000,000 one trillion (12 zeros)

1,000,000,000,000,000 one quadrillion (15 zeros)

1,000,000,000,000,000,000 one quintillion (18 zeros)

Life on EarthProkaryotic and Eukaryotic Cells

All cells on Earth are either prokaryotic or eukaryotic.

Prokaryotic cells are smaller and simpler in structure.–Typical prokaryote is around 5 μm

They probably resemble the earliest cells to arise on Earth.

They often have a cell wall but it is not made of cellulose like plants, it is made of a substance called peptidoglycan.

How big are cells? (p44)

Bacteria are prokaryotes, they are smaller than animal or plant cells which are eukaryotic

Prokaryotic means NO nucleus Eukaryotic cells have a nucleus, in

which they keep DNA

Life on Earth

Prokaryotic and Eukaryotic Cells Prokaryotes do not have a true nucleus. They don't have organelles

Figure 2.17b

Life on Earth

Prokaryotic and Eukaryotic Cells

Eukaryotic cells are much more complex.

− Have true nucleus surrounded by a membrane

− Also have (in most cases) membrane-bound organelles with specialized jobs

STUDY GUIDEKnow the difference and similarities between prokaryotes and eukaryotes

Q1. Which one does not have a nucleus?

Q2. Which one has organelles?

Q3. Which one is bigger?

Q4. How big is a typical prokaryote and eukaryote?

Q5. In what scale do we describe the size of cells?

Q6. Know which is bigger and smaller

– Arrange these from smallest to biggest:

10cm 50mm 1m 600nm 90μm

Life on Earth

Eukaryotic Cells (p48)

Figure 2.18

Differences

Can you find the differences between plant and animal cells?

Except:

Cytoplasm – the entire contents of the cell (except the nucleus) surrounded by the plasma membrane

Cytosol – the fluid portion of the cytoplasm

Look inside a cell

Tour of an animal cell

Tour of a plant cell

- surrounds the cell

- regulate what comes in and what goes out

- semipermeable (more specifically it is partially permeable)

- maintain an internal environment different from the outside

– Hydrophobic core

• many polar molecules cannot cross

Membrane

Fluid mosaic

http://www.dnatube.com/video/360/Fluid-Mosaic-Model

- all plant cells have a cellulose cell wall

- not found in any other cells

- tough often flexible

- in conjunction with pressure exerted by the vacuole gives the cell rigidity

- like air in a tire

- only found in eukaryotes, 2 membranes

- houses the DNA

- studded with holes called nuclear pores

- Through which the DNA can “communicate” with the cell

- nucleolus is where ribosomes are built

- bounded by a double membrane

- important in the conversion of food into usable cellular energy – cellular respiration

- usable cellular energy is the molecule ATP

- folded up inner membrane increases surface area

STUDY GUIDEBe able to identify in a cell diagram and know the function of the

following:

a. Plasma membrane

b. Cell wall (plants)

c. Nucleus

d. Mitochondria

- only found in plants and green algae (plant ancestors)

- site of photosynthesis

6CO2+6H20 → C6H12O6 + 6O2

- 2 membranes

- pigments (chlorophyll) in chloroplast make plants green

- membrane enclosed sac of digestive enzymes

- recycles molecules and damaged organelles

- found in both prokaryotic and eukaryotic cells

- take instructions from DNA and build proteins

- can be free floating or attached to the endoplasmic reticulum

- 2 types – rough and smooth

- Rough ER – covered in ribosomes

- major site for protein production in the cell

- proteins made here are usually secreted by the cell or become part of the plasma membrane

- Smooth ER – no ribosomes, varied function

- detoxifying harmful substances, lipid synthesis

- vesicles are pinched off pieces of ER

- protein containing vesicles from the ER fuse with golgi

- the proteins are modified, sorted, packaged and sent out to their destinations in new vesicles

ER to Golgi

http://www.youtube.com/watch?v=rvfvRgk0MfA

From 1.26 onward

- protein containing vesicles from the ER fuse with golgi

- the proteins are modified, sorted, packaged and sent out to their destinations in new vesicles

STUDY GUIDEBe able to identify in a cell diagram and know the function of the

following:

e. Chloroplast (plants)

f. Lysosome

g. Ribosomes

h. Rough and smooth ER

i. Golgi apparatus

- found in most eukaryotic cells, though it is absent in higher plants and most fungi

- microtubule formation

- cell division – move chromosomes around

- cilia and flagella

- protein fibers

- give shape to the cell

- hold and move organelles

- including transport vesicles

- involved in cell movement

- can occupy 90% of a plant cell

- contains many dissolved molecules

- eg sugars and pigments

- pressure of vacuole pressing against the plant cell wall gives structural support

- allows plants to stand upright

Cell as a factory

STUDY GUIDEBe able to identify in a cell diagram and know the function of the

following:

j. Centrioloes

k. Cytoskeleton

l. Central vacuole (plants)

Be able to relate the organelle with the factory job function

Identify the cell components

1

23

45

6

7

8

9

12

34

5

6

7

8

9

1011