blast from the past! define: manipulated variable responding variable

BLAST FROM THE PAST!1.Define: Manipulated variable

Responding variable2.Convert: 34,758,900m = _________km

1.6L = ______ ml3.Given: MV = amount of artificial light

RV = plant growthWrite a possible formal hypothesis.

4. Describe: The difference between a qualitative and a quantitative observation. Include examples.

1. Define: MV – variable that is changed on purpose by the scientists

RV – variable that changes b/c of the MV; variable that is measured in the experiment.

2. Convert: KHD b/u dcm34,758.9 km1600mL

3. Hypothesis: If the amount of artificial light is related to plant growth, then increasing the amount of light will make the plant grow taller.

4. Describe: Qualitative Observation – Describing an object based on one’s 5 senses. Ex. The potato feels soft

and bendy. Quantitative Observation –

Describing an object based on some type of measurement. Ex.

The potato has a mass of 1.7 g.

CHEMICAL COMPOUNDS IN CELLS

PAGES 74-78 IN TEXT BOOK

So What’s an ELEMENT?• Any substance that cannot be broken

down into simpler substances. Everything on this planet, living or non-living, is made up of elements.

• About 100 different elements are found on the Earth

• Each element has its own characteristics and properties– Ex – Sulfur in its pure form is a yellow,

solid, crystal.

• The smallest unit of an element is an atom. Elements are only made up of one kind of atom.

Before we can talk about “chemical compounds” in cells, we have to find out what a compound IS.

• COMPOUND – two or more elements that combine.

• This is one molecule of a compound called ammonia NH3

– 1 atom of Nitrogen– 3 atoms of Hydrogen

Chemical compound called ammonia or NH3.

This is a molecule of water

• 1 atom of Oxygen• 2 atoms of Hydrogen

How many atoms of each element do you see in this molecule of glucose?

Compounds• Carbon dioxide CO2

• Water H2O

• Sugar C6H12O6

• Salt NaCl

• Hydrochloric acid HCl

The Compound Called Water

• Water makes up about 2/3 of our body.• All chemical reactions take place in water• Water gives the cell its size and shape• Water is also in the environment outside

the cell as well

Inorganic vs. Organic Compounds

• Organic compounds: compounds that contain carbon (except CO2)

– Example – glucose C6H12O6

• Inorganic compounds: compounds that DO NOT contain carbon– Examples – water (H2O),

table salt (NaCl)

Important Organic Compounds• The four main organic compounds found

in all living things are:– Carbohydrates– Lipids– Proteins– Nucleic Acids

• They all have one thing in common – they have the carbon atoms in them

CARBOHYDRATES

• Job: Give the cell energy

• Simple carbohydrates are sugars (C, O, H)– Lactose– Sucrose– Glucose

• Complex carbohydrates are starches.– Cellulose – plant cell walls are made up of

cellulose– Starches stored in plants (potatoes, pasta, rice)

LIPIDS• Job: Back up energy

reserve for the cell.

• Hydrophobic – cannot mix with water due to their structure

• Cell membranes are made mainly of lipids

PROTEINS • Job: Form parts of the cell

membrane and make up many of the cell organelles

• Made up of smaller molecules called amino acids– There are 20 amino acids– The structure and function of a

protein depends on how many and in what order amino acids are found in the molecule.• Think of amino acids like

letter in the alphabet

A Special Type of Protein

• Enzymes: type of protein that speeds up a chemical reaction in a living thing.– Acts like pouring gasoline

on a fire. (Speeds up the reaction of the fire.)

– Example: Enzymes in your saliva break down starch into sugars in your mouth, speeding up the digestion process.

Enzymes are put in some detergents to help remove tough stains. They speed up the process of breaking down stains on our clothes.

Cheese is made by inserting enzymes into milk.

NUCLEIC ACIDS• Job: Holds instructions

for everything that goes on in a cell.

• Two kinds– DNA – carries information

about an organism; passed from parent to offspring

– RNA – plays a role in making proteins

C, H, O , N, P