What is Biology?

Let’s PracticeTell if the object is living or nonliving.

NonlivingLiving

Living

Living LivingLiving

Nonliving

So what makes something “alive”?(What characteristics do all living things have in

common?)

Biologists have come up with the following 7 characteristics for all living things:

Living Things:

1. Use Energy2. Made of Cells3. Respond to a Stimulus4. Reproduce5. Grow & Develop6. Have a Genetic Code7. Adapt to their Environment

Notice: Motion is NOT on this list!

Unit 1:Structure and Function

of Life

What is science?

• Science is an organized way of gathering and analyzing evidence about the natural world.

– Way of observing

– Way of thinking

– Way of “knowing”

• Science is not a “thing” it’s a process!

Science as a process

• The process of science is….1. Dealing ONLY with the natural world around us

2. Collecting and organizing information they find, looking for patterns.

3. Proposing explanations based on evidence.

• Scientists want to find explanations for the world around us…one goal of science is to investigate, understand and analyze data, and provide explanations about the world.

Q: How do we explore the world around us?

• What senses do you use?

• Science is based on observations.

Observations lead to Questions

Questions lead to Experiments

This is the

Scientific Method!

HypothesisA prediction based on an observation

• Only useful if it can be tested• Always very specific

• It’s NOT a question – always phrased as a statement of what you BELIEVE.

Bad Hypothesis Good Hypothesis• Hermit crabs like colorful

shells

• Plants will grow better when given Miracle Grow.

• Hermit crabs choose colorful shells over drab shells

• Plants will grow taller when given Miracle Grow

Experimentation• After you form your hypothesis, you need to test

it! An experiment is a designed, planned procedure.

In your experiment you must have 2 groups:

Experimental Group Control Group

• Receives the treatment

• This is the group that you will be exposing to the procedure

• Receives NO treatment (placebo)

• This group does not get treated, it is used to represent what “normally occurs in nature when left alone”

Data – information gathered from observations

• Quantitative Data: use numbers and measurements for observations

– Examples:

• Qualitative Data: use descriptive terms for observations (cannot be counted

– Examples:

What Qualitative or Quantitative observations can you make?

What Qualitative or Quantitative observations can you make?

Variables

• What is a variable?

– A factor or characteristic that can change

– Something that can be causing the observations you see

• Ex: temperature, light, time, etc.

Controlled Experiments

• You always want your experiment to be a controlled experiment.

• Controlled experiments only testing ONE variable at a time.

Ex: think controlled experiment – we “control” the one variable we want to test.

Why can’t we change multiple variables?

Light

Why can’t we change multiple variables?

Types of Variables

Since we only want to test one variable, weneed to categorize our variables.

• Independent variable: The variable that you are testing (manipulated variable).

• Dependant variable: The variables that are affected by the experiment (responding variable). It is an action or an outcome!

Experimental Group

The group that receives the treatment (test)

Control Group The group that receives no treatment

Variable A factor or characteristic that can change

Independent Variable

The characteristic (variable) that you are testing

(manipulated variable)

Dependent Variable

The characteristic (variables) that are affected by your experiment

(responding variables)

Patty Power

Mr. Krabbs wants to make Bikini Bottoms a nicer place to live. He has created a new sauce that he thinks will reduce the production of body gas associated with eating crabby patties from the Krusty Krab. He recruits 100 customers with a history of gas problems. He has 50 of them (Group A) eat crabby patties with the new sauce. The other 50 (Group B) eat crabby patties with sauce that looks just like the new sauce but is really just a mixture of mayonnaise and food coloring. Both groups were told that they were getting the sauce that would reduce gas production. Two hours after eating the crabby patties, 30 customers in group A reported having fewer gas problems and 8 customers in group B reported having fewer gas problems.

1. Which people are in the control group?

2. What is the independent variable?

3. What is the dependant variable?

4. What should Mr. Krabs’ conclusion be?

Why do you think 8 people in group B reported feeling better?

Group B (mayo + food coloring)

The new sauce

The body gas

That the new sauce works, and his hypothesis was correct!

Placebo Effect

Direct vs. Indirect RelationshipsWhen comparing data, scientists are sometimes able to conclude

how things are relate to each other.

Direct Relationship:Two variables change in the samedirection. As one variable increases, the other also increases

Indirect/Inverse Relationship:Two variables change in the opposite direction. As one variable increases, the other decreases

Organization of Living Things

• Some organisms are unicellular– Only made of one cell

– Make up most of the living things on Earth!!!

– Have everything they need to survive in one cell.

– Colony: a group of cells that live together but maintain their own individual existence

• Example: Bacteria tend to live together in group but are individuals.

Unicellular Organisms

• Some organisms are multicellular– Made of many cells.

• In multicellular organisms, cells exhibit specialization.

– They take on specific jobs and look different from each other.

• The cells also exhibit division of labor. – They split up the work of the organism.

Multicellular Organisms

• In multicellular organisms, the cells specialize to perform specific functions. • Examples: bone cells, skin cells, nerve

cells, root cells, leaf cells

Smooth muscle Nerve cell Leaf cell Red Blood Cell

Specialization/Labor Division

Levels of Organization• Tissues—Groups of similar cells that work

together to perform a specific function.

– 4 major tissue types in animals

• Epithelial tissue

• Connective tissue

• Muscle tissue

• Nervous tissue

Epithelium (Human Skin)Muscle Tissue

• Organs—structures made of different types of tissues that work together to perform a specific function.

– Examples• Heart

• Lungs

• Stomach

• Liver

• Plant Roots

• Plant Stems

• Plant Leaves

Levels of Organization

• Organ Systems—Groups of organs that work together to perform a specific function.

– Examples:• Digestive system

• Circulatory system

• Respiratory system

• Nervous system

• Muscular system

• Skeletal system

• Integumentary system (skin)

• Vascular system in plants

Levels of Organization

• Organism—A complete, individual living thing.

– Examples:

• A single person

• A single plant

• A single bacterium

• A single protist

Levels of Organization

Basis of Matter/Chemistry

What do you already know about matter?

• Is all matter visible?

• Does all matter take up space?

• What is a chemical reaction?

• Matter is anything that has mass and takes of space.

• The basic unit of matter is the atom.

• The atom is made up of 3 parts:

– Protons

– Neutrons

– Electrons

• Atoms joined together make chemical compounds

Chemical Reactions

• A chemical reaction is a process that changes

one set of chemicals into another.

• Reactants: Compounds/Elements that

enter the reaction

• Products: Compounds/Elements that are

produced by the reaction

• Reactions involve changes in bonds between atoms

*bonds break = energy is released

*bonds made = energy is absorbed/stored

Enzymes

Chapter 2

What is an enzyme?

Enzymes -proteins that act as catalysts. -speed up chemical reactions in cells-very specific, catalyze only one

reaction-named from the reaction it catalyzes

(ends in –ase)Substrates- Reactants of enzyme-catalyzed reactions

• substrates bind to a site on the enzyme called the activation (active) site.

• active site & the substrates have complementary shapes

How do enzymes work?

• Enzymes are known as “catalysts”.

• Catalysts speed up chemical reactions by lowering the “activation energy” to get a reaction started.

1. It takes lots of energy to get a reaction started.

2. Having a catalyst present allows less energy to be used to get a reaction started.

Catalysts (enzymes) help chemical reactions happen with less energy.

Enzyme productivity

• In order for enzymes to work efficiently, they have to be in the right environment.

• There are some things that affect how well enzymes work. They are:

– Temperature

– pH (acid or base)

– Activators & Inhibitors (supplements, drugs, poisons, etc)

• Temperature effects enzyme activity

• Each enzyme has its own optimum temperature

• pH (acidity) effects enzyme activity

• Each enzyme has its own optimum pH

At what pH do both enzymes have the same activity?

Which enzyme has an optimum pH of around 6.5?

Enzyme Usage

• Enzymes are NEVER used up in a reaction, they get recycled and used again and again.

MACROMOLECULES(Biological Molecules)

CHAPTER 2

Crash Course: Biological Molecules

What’s the deal with carbon?

Carbon is essential to life!

Our bodies are made up of thousands of carbon-containing molecules called Organic molecules!

Organic molecules = Contain the element Carbon!!

Macromolecules• Organic Molecules are called

Macromolecules

– Carbohydrates

– Lipids

– Proteins

– Nucleic Acids

• Organic molecules are built using building blockscalled MONOMERS– Mono: 1

• When you put together those building blocks you build large organic molecules called POLYMERS– Poly: many

Carbohydrates

Chapter 2

Carbohydrate Purpose

• Carbohydrates are SUGARS made of carbon, hydrogen, and oxygen atoms in a 1:2:1 ratio

• Function: Carbohydrates provide energy for the brain and ½ of energy for muscles and tissue

Carbs are not equal

Simple Carbohydrates: Sources for Instant energy (Monosaccharides)

Complex carbohydrates: Store houses for energy (Polysaccharides)

Simple Carbohydrates (simple sugars)

Monosaccharides(monomers)

Glucose: essential energy source

Fructose: the sweetest, occurs naturally in honey & fruits. Addedto many foods in the form of

high fructose corn syrup.

Complex Carbohydrates

Polysaccharides (Polymers)

–Glycogen

–Starch

–Cellulose

For humans & animals, after we eat, whatever energy (glucose) is not used right away is stored as glycogen.

Good for short term storage (~1 day)

Stored in muscles & the liver

Complex Carbohydrates: Glycogen

Plants store LOTS of energy, in the form of starch.When humans eat plants we take in this energy.

Most common carbohydrate in our diet.

Complex Carbohydrates: Starch

Cellulose is the main building material for plant cell walls.

Plants are made of this complex carbohydrate.

When humans eat plants, cellulose is not easily digested.

Animals digest cellulose more easily.

Complex Carbohydrates: Cellulose

So for humans…. if even the biggest carbohydrate (glycogen) only stores energy

for about 1 day….

How do we store energy more long term?

FAT! = Lipids

LipidsChapter 2

Lipid Purpose

Lipids are made of carbon, hydrogen & oxygen

(just like carbs)

• Function: Store energy long term, and make cell membranes.

• Examples: Fats, waxes, cholesterol, oils

Lipid Structure

Lipid MONOMERS are made of two parts:

• 3 Fatty acid chains linked to

• 3 glycerol groups

Lipids are not equal

Saturated

Unsaturated

FATTY ACID CHAINGLYCEROL

Saturated Lipids

• Saturated Lipids have ONLY SINGLE BONDS in its fatty acid chain

• UNSATURATED LIPIDS HAVE ONE

OR MORE DOUBLE BONDS IN

ITS FATTY ACID CHAIN, CREATING

A KINK IN THE CHAIN

FATTY ACID CHAIN

UNsaturated Lipids

• tend to be solids – chains can stack closer

together

• TEND TO BE LIQUID (OILS)

• CHAINS CAN’T STACK CLOSE

TOGETHER BECAUSE OF KINK IN

CHAIN

Lipid Characteristics• Lipids are also waterproof molecules because they have

non-polar bonds (equal sharing of electrons)

• Think of oil & water!

They don’t mix!

WATERREPELLENT

TAIL

ProteinsChapter 2

Purpose of proteins

Proteins do LOTS of things in your body

Our bodies contain thousands of proteins keeping you alive!

• Enzymes – regulating chemical processes and helping you digest food

• Antibodies – protecting your body from bacteria

• Endorphins – proteins in your brain that make you feel emotions

Protein Structure

• Monomer = Amino Acid

–Chains of amino acids = Polypeptide Chains

• Polymer = Protein

The “R” group is where one of twenty different side chains can attach, making twenty different amino acids – which will determine the protein’s function.

AMINO ACIDS ARE THE

BUILDING BLOCKS

(MONOMERS) OF

PROTEINS!

Building proteins from amino acids

Amino acids bond together through peptide bonds.

Peptide bonds

• Condensation reaction between two amino acids

• Produces H2O as a by-product

• A chain of amino acids is a polypeptide.

NOTE** This is the first time that nitrogen has shown up!

Importance of Nitrogen

• Nitrogen is one of the most abundant chemicals on earth

– all around us in the atmosphere and in the air we breathe.

• We can’t use nitrogen gas

Must eat it to use it!

Nucleic Acids

Chapter 2

Purpose of Nucleic Acids

Nucleic Acids form and transmit genetic information by making proteins.

Nucleic acids are your DNA and RNA!

Genetic information is passed down to new cells during the process of MITOSIS or cell splitting.

Structure of Nucleic Acids

Nucleic acids are made up of pieces (monomers) called Nucleotides.

Each Nucleotide has 3 parts:

– Deoxyribose (5-carbon sugar)

– Phosphate Group

• Only Macromolecule containing phosphorous

– Nitrogen Base

It’s the combination of these nucleotides that make up an entire dna or rna strand!

Nucleotide Structure

Macromolecules Summary

C H O N PLipid

Carbs.

Protein

NucleicAcids

What is in each Macromolecule?

Carbon Hydrogen Oxygen Nitrogen Phosphorus

Homeostasis- a condition or process in which organisms use energy to keep

conditions inside their cells constant or regular.

All living things respond to a stimulus!

Living things respondto immediate and long-term changes in their environment (shiver when cold, change fur color, plants bend toward light)

Negative Feedback: The body doesn’t like what is happening so it tries to oppose the effect of the stimulus. **Sweating when it is hot out cools your body temperature

**How the body maintains homeostasis

Positive Feedback:Response enhances the effects of the original stimulus.**Contractions during childbirth

Types of Responses

Examples: Responding to Stimuli

a. dogs pant when hot

b. pupils dilate in lower light levels

c. humans sweat when body gets too hot

d. reflexes – touch hot stove, fight/flight

Let’s Try It

• I will turn off the lights for a minute or two.

• Partner up and look at each other’s eyes.

• What happens when I flip the light back on?

• Why does this happen?

Crash course: Membranes and Transport

• Cell membranes are made up of lipid bilayers

• It regulates what enters & leaves the cell.

• Lipids have a water-loving end (hydrophilic) and a water-hating end (hydrophobic)

Made of two layers since there is water inside and outside of the cell, so the hydrophobic ends don’t like either side

• Among the lipid bilayer are larger protein molecules.

• Proteins form channels or pumps that move material across the membrane.

Fluid Mosiac Model:All different cells make

up membrane

Selectively Permeable:

– Some substances can cross the membrane and some cannot.

• Also called semipermeable membrane

• If a substance can cross – membrane is permeable

• If a substance cannot cross – membrane is impermeable

– Without selective permeability, the outside and inside of a cell would have the same contents

Concentration Gradient• concentration difference between regions of Many

solutes (high concentration) and few solutes (Low concentration).

• concentration gradient will be to move from High concentration to low concentration

• This is an effort to reach equilibrium (same amount of particles on each side of the membrane)

PASSIVE• Does not require energy

• Goes with the concentration gradient (high to low)

• Simple Diffusion, Facilitated Diffusion, Osmosis

ACTIVE• Requires energy from ATP

• Goes against the concentration gradient (low to high)

• Active Transport, Endocytosis, Exocytosis

• In any solution, particles will tend to spread out. (ex: sugar in tea)

• Diffusion: the movement of particles from highconcentration to low concentration.

• Diffusion is the driving force behind movement of substances across cell membranes.

• If a substance is present in unequal concentrations on different sides

of the membrane it will continue to move back and forth across the

membrane to obtain an equilibrium.

• Once Equilibrium is reached the solute particles will still move across

the membrane but at equal rates in and out.

• Particles are moving through a transport protein with the concentration gradient (from high to low concentration)

• Large molecules won’t fit through the membrane

• Particles must move through a protein channel

• Does not require energy

• The movement of water through a semipermeable membrane by facilitated diffusion is called osmosis.

• TYPE OF FACILITATED DIFFUSION

• Water has a tough time passing through membranes because of Hydrophobic lipid ends.

• Water must travel through special proteins like other molecules

– These proteins are call aquaporins

• Water will move across the semipermeablemembrane to the side with higher concentration of solutes.

Barrier is permeable to water,but not the purple solute

• Water will move across the barrier until an equilibrium is reached (isotonic solution).

• At the beginning, the more concentrated sugar side was hypertonic, or “above strength”

• The less concentrated side was hypotonic, or “below strength”

Isotonic

HypertonicHypotonic

• The word "HYPO" means LESS, in this case there are less solute molecules outside the cell, since salt sucks, water will move into the cell.

• When water moves intothe cell, the cell grows larger.

• The word "HYPER" means more, in this case there are more solute (salt) molecules outside the cell, which causes the water to be sucked in that direction.

• If water is moving out of the cell, the cell shrinks

• The cell may die.

This is why it is dangerous to drink sea water – It speeds up dehydration(and death) if your stranded.

Which would cause a cell to burst?

Answer: B

There are less water molecules outside the cell then inside, which would cause the water to move into the cell.

You can also tell by looking at the arrows, the arrow of water coming in is much larger than the water going out. Showing that water will rush into the cell.

• Particles move from low to high concentration against concentration gradient

• Requires ATP energy

• Import of large particles into the cell

• The plasma membrane surroundsand brings larger particles into the cell

– Phagocytosis – cell “eating”

– Pinocytosis – cell “drinking”

• Requires energy

• The export of large particles such as waste out of the cell

• Proteins, hormones, and other substances are secreted from cells in this manner