unit 5 – section 7.1 cell - the basic units of all living organisms. there are thousands of...

Unit 5 – Section 7.1Cell - The basic units of ALL LIVING organisms. There are thousands of different kinds of cells, based on their functions. (Building blocks of Life)

**Average adult is made up of approx. 30-40 trillion cells

**Placed end to end, they would stretch around the earth 47 times. A ten year old has about half that many cells. If you could count them at a rate of one cell per second, it would take you over 2600 years to complete the task.

Anthony vanLeeuwenhoek -Contributed to the study of Science by making some of the first lenses and microscopes. (Also observed the 1st living cells)

Robert Hooke - Was the 1st person to observe and name cells. He was looking at dead tree bark

Cell Theory - Certain facts are true of all cells regardless of the type. The theory was proposed by two Scientists Mattias Schleiden & Theodore Schwann

The Cell Theory States that . . .

1. All living things are made of one or more cells. (Unicellular or Multicellular)

2. Cells are the basic structural & functional unit of all living organisms.

3. All cells come from other cells

Organelles - Small membrane-bound structures found in the cell that have a specific function (Like organs in the body).

Prokaryotes - Cells that do not contain membrane bound organelles (No Nucleus, more disorganized).

- Example Bacteria

Eukaryotes - Cells with organelles that are surrounded by a membrane (Have a Nucleus, more organized)

- Most cells that we think of are Eukaryotic.

Unit 5 – Section 7.2 & 7.3Cell Organelles

Cell Membrane (Plasma Membrane)Plant & Animal

- Function: Regulates material in and out of cell

- Appearance: This skin made of Lipids - Location: Outer boundary for cells **Selective permeability a process used to maintain homeostasis in which the plasma membrane allows some molecules into the cell while keeping others out.

What would happen if the cell membrane was not selectively permeable?

Nucleus Plant & Animal - Function: Controls cell activities - Appearance: Large spherical structure - Location: Typically in the middle of the cell

Cytoplasm Plant & Animal - Everything inside the cell except the nucleus

- Includes fluids and organellesNuclear Membrane Plant & Animal Function: Regulates material in & out of nucleus

Appearance: Similar to plasma membrane Location: Surrounding the nucleus

Cell Wall Plant Only Function: Protects and supports the cell Appearance: Thick rigid structure Location: Outer most structure of plant cells

Nucleolus Plant & Animal Function: Synthesizes (makes) ribosomes & RNA

Appearance: Small spherical structure Location: Found within the nucleusChromosomes Plant & Animal Function: The cell’s instructions (Made of DNA)

Appearance: Typically not visible, long strands

Location: Within the nucleus

Ribosomes Plant & Animal Function: Protein Makers (Repair/Make Cells)

Appearance: Smallest spheres (most numerous)

Location: Endoplasmic Reticulum & Cytoplasm

Endoplasmic Reticulum Plant & Animal Function: Transport Proteins & Minerals

Appearance: Smushed stack of pancakes

Location: Attached to nuclear & cell membranes

Vacuoles/Vesicles Plant / Animal Function: Stores nutrients, water, & wastes

Appearance: Vacuoles=Large, Vesicles = Smaller

Location: Cytoplasm

Mitochondria Plant & Animal Function: Breakdown food & release energy

Cell Respiration (Powerhouse of cell)

Appearance: Oval shaped structures, medium size

Location: Cytoplasm

Golgi Complex/Body Plants & Animals

Function: Package, distribute, transport proteins

Appearance: Stacks of flattened tubes

Location: Cytoplasm

Microtubules & Microfilaments Plant & Animal Function: Support & Maintain Cell’s Shape (skeleton)

Have a role in mitosis (cell reproduction)

Appearance: Tiny rods & strings Location: CytoplasmCentrioles Animal Function: Pull apart chromosomes during Mitosis

Appearance: Short rod or cylinder shaped Location: Cytoplasm

Lysosomes Animals Function: Enzymes used to breakdown foreign

material & food Appearance: Looks like vesicle Location: CytoplasmChloroplasts Plant Function: Make or store food (Photosynthesis)

Appearance: Green disc shaped, medium sized

Location: Cytoplasm **chloroplasts contain green pigment: Chlorophyll

Structures for Locomotion (Movement)Cilia--short, numerous, hair-like projections that move in a wavelike motion.

Flagella—whip-like tail/projections

Unit 5: Basic Cell Functions

1) Nutrition - Cells must take in food,

water, & materials** These are used for fuel, growth, &

repair of the cell.2) Excretion - Cells must get rid of wastes.** As cells take in products, wastes

are left over which must be eliminated.

Basic Cell Functions Continued. . .3) Respiration - The breakdown of the food using oxygen. This releases the energy for the cell to use.

** Done by the mitochondria – ATP is made4) Reproduction - Cells reproduce by the process of Mitosis (Cell Division).

** Many cells continue to grow as they live and they simply get to big to survive.

Unit 5: Section 6.2Water - Is one of the most important compounds in living organisms (Makes up 70-95% of most organisms). It is used primarily to help transport substances.

**It is one of the few substances that expands when it freezes and contracts when it heats up to become a liquid.

Diffusion - The movement of molecules from an area of high concentration to an area of low concentration, until equilibrium is reached.

- All molecules are in constant motion so diffusion doesn’t require any added energy, although adding energy can increase the rate.

- Diffusion will happen faster the more the molecules move. This will be determined by its state of matter: Solid, Liquid, or Gas.DEMO Sugar cube race

- Diffusion will happen faster with increased:

temperature, pressure, and concentration

- There must be two different areas of concentration, one higher and other lower for diffusion to occur: Diffusion Gradient

- In order for diffusion to move substances in and out of a cell, its membrane must allow things to pass through: Permeable

Equilibrium - When molecules are evenly spread out in a given area or between two different areas.

Diffusion Problems

A) 25 mL of H2O & 3 g of Food

B) 60 mL of H2O & 6 g of Food

1. If diffusion was to occur, what would

move & which way would it go?

A) 35 mL H2O & 5 g waste

B) 50 mL H2O & 15 g waste

1) If diffusion was to occur, what would

move & which way would it go?

A B

A B

Unit 5 – Section 8.1Osmosis is Diffusion – The diffusion of water only

Osmosis - The tendency for water to move from an area of high concentration to an area of low concentration.

** A diffusion gradient and a permeable membrane are still needed. Most of the time water will diffuse when other molecules won’t (water is very small).

** The liquid part (Water) of a solution is the Solvent

** The solid particles (Nutrients/Wastes) dissolved in the solvent are called Solutes.

- Diffusion and Osmosis deal with concentrations of solute versus solvent and not just amounts.

Exampes

Hypertonic - A solution that contains a higher concentration of solute in it compared to another solution.

(water flows out of cell causing cell to shrink)

Hypotonic - A solution that contains a lower concentration of solute in it compared to another solution.

(water flows in the cell causing cell to expand)

Isotonic - When two solutions have the same or equal concentrations of solute as each other.

(water molecules move into and out of cell at the same rate so cells retain normal shape)

Osmosis Problems

A) 25 mL of H2O & 3 g of Food

B) 60 mL of H2O & 6 g of Food

1. If osmosis was to occur, what would

move & which way would it go?

A) 35 mL H2O & 5 g waste

B) 50 mL H2O & 15 g waste

1) If osmosis was to occur, what would move & which way would it go?

A B

A B

Water will move by osmosis from a ____________

solution to a ____________ solution

Solutes will move by diffusion from a ___________ solution to a ____________ solution

Hypotonic

Hypertonic

HypertonicHypotonic

Active Transport - Is used when diffusion doesn’t work. It requires energy to be used (ATP).

- It works like electric revolving doors called

Active Sites. - Molecules moving in or out must fit these active sites like puzzle pieces (Enzymes/substrate) or they are not permitted to move across the membrane.

- The active sites can be turned on or shut off to regulate what gets in/out and when

3 Situations when Active Transport is used Instead of Diffusion

1) The molecules are too large to diffuse the cell membrane pores.

2) The molecules moving are ions (charged +/-)

3) The cell is trying to move the molecules against the diffusion gradient (Low to High Concentration).