Beginning of year Bio test

Life

Life

A self-sustaining chemical system capable of Darwinian evolution.

Cell

Smallest unit of life that can still fulfill all characteristics of life.

What is a prokaryote?

An organism whose cells don’t contain nuclei.

What is a eukaryote?

An organism whose cells contain nuclei.

Nucleus

Sack that holds DNA

Mitochondria

Uses oxygen to break down glucose to get energy.

Examples of prokaryotes

Bacteria, archaea

Examples of eukaryotes

Protist, Plant, fungi, animal

How much of life do prokaryotes make up?

99.9%

What are the two types of cell reproduction?

Sexual and asexual

What is asexual reproduction?

• One organism splits into 2 producing a clone

• Most common type of cell reproduction

What are the benefits of asexual reproduction?

• Fast

• Only requires 1 parent

• well adapted parents will have well adapted kids

What are the cons to asexual reproduction?

Bad parents will have poor offspring

What is sexual reproduction?

• 2 organisms produce one or more genetically unique offspring

• Very rare

What are the benefits of sexual reproduction?

Poorly suited parents can create well suited kids

What are the cons of sexual reproduction?

• Slow

• 2 parents

• well suited parents can have poorly suited kids

Source of raw materials for heterotrophs

Other living things

Source of energy for heterotrophs

Combusting sugar and other biomolecules

Examples of heterotrophs

You, bacteria, fungi, and others

Source of raw materials for phototrophs

Combine CO2 from atmosphere into biomolecules

Source of energy for phototrophs

Sunlight

Examples of phototrophs

Bacteria, archaea, protists, plants

Source of raw materials for chemotrophs

Combine CO2 dissolved in seawater into biomolecules

Source of energy for chemotrophs

Chemical reactions from the environment

Examples of chemotrophs

Archaea

Definition of homeostasis

Maintenance of a constant internal environments despite external changes.

Darwinian evolution

• Organisms change over time, described by the Theory of Natural Selection

• Organisms with beneficial traits reproduce more, so good traits become more, bad traits become less common

Speciation

If a population becomes separated, the two new populations can evolve into new species.

LUCA

Last Universal Common Ancestor. The organism that all others evolved from.

3 main groups of organisms

Bacteria, archaea, and eukaria

Bacteria (oldest)

• Prokaryotic cells

• Cells are unicellular

• Have unique DNA and proteins

Archaea

• Prokaryotic cells

• Cells are unicellular

• Have similar DNA and proteins as eukaryotes

Eukaria (newest)

• Cells have nucleus and other organelles

• Cells are mainly unicellular, but can be multicellular

• Have similar DNA and proteins as archaea

What are the 4 kingdoms in Eukaria

• Protists/Protista (oldest)

• Plants/Plantæ

• Fungi

• Animals/Animalia (newest)

Who developed our current scientific method?

Sir Francis Bacon

5 steps of the scientific method

1. Choose a research topic (question/problem)

2. Research background (knowledge already known)

3. Construct hypothesis

4. Perform investigation (test hypothesis)

5. Analyze results + share conclusions

Researching Background information

• Read

  • Primary literature

  • Textbooks

• Speak

  • Speak to experts in the field at local colleges, universities, hospitals, or research centers

• Online

  • Identify the website: trust places where mistakes get you fired

  • Identify the author: is it a real person? Are they an expert?

  • Ensure it is serious: do other people discuss it?

Definition of Hypothesis

Statement giving a cause for your observation: it is what will be tested in the experiment

Criteria for a good hypothesis

• Testable

• Fits into existing information

• Can be done with your resources

• Contributes information whether right or wrong

True or false: Your goal is to always prove your hypothesis is true

FALSE

Criteria for a good experiment

• Answers one question

• Is definitive

• Has appropriate controls and is standardized

• Has limited variables

• Has a large sample size or replicates (multiple runs) to protect against outliers

• Can be repeated by you and others

Measurement system used to standardize experiments

The SI measurement system (Le systéme international d’unités)

SI unit for length

Meters (m)

SI unit for volume

Liter (l)

SI unit for mass

kilograms (kg)

SI unit for temperature

Kelvin (K) / degrees Celsius (°C)

SI unit for time

Seconds (s)

Micro (µ)

1/1,000,000

Milli (m)

1/1,000

Centi (c)

1/100

Base unit

1

Kilo (k)

1,000

Steps for dimensional analysis

• Rewrite the value and unit you are given to start

• Multiply by a fraction:

  • Numerator: the prefix value and unit you WANT

  • Denominator: the prefix and unit you already HAVE

Theory

A hypothesis that has never been shown to be wrong after repeated testing. It explains an observation.

Law

Describes a universal phenomena that is known to happen, but we have no explanation why.

3 categories of matter

• Elements

  • Substances made up of only one kind of atom. (eg. gold, carbon, oxygen)

• Compounds

  • Two or more atoms bound together, forming a new substance. (eg. water (H2O), sugar (C12H22O11), table salt (NaCl))

• Mixtures

  • Two or more chemicals blended together. Not chemically bound. (eg. Blood, soda, sand)

Elements

• There are 118 known elements

• Only 92 exist in nature (most in trace amounts)

• All are listed in the Periodic Table of Elements

Big 6 elements

• Carbon (C)

• Hydrogen (H)

• Oxygen (O)

• Nitrogen (N)

• Phosphorus (P)

• Sulfur (S)

(CHONPS)

Less important but still important elements

• Calcium

• Magnesium

• Iron

• Potassium

• Sodium

• Chlorine

Electron Cloud

• Biggest part of an atom

• Contains electrons

Electrons

• So small, practically weightless

• Charge of -1

• Involved in bonding

• Neutral atoms: # of electrons = # of protons

Nucleus

• Solid center —> very small

• Made up of neutrons

• Made up of protons

Neutrons

• Weigh 1 amu (or Dalton)

• Neutral charge

Protons

• Weigh 1 amu (or Dalton)

• Charge of +1

• Every element has a unique number of protons (the atomic number)

Isotopes

Atoms with equal numbers of protons but different numbers of neutrons (same atoms but different mass, eg. Carbon-12 and carbon-14)

Ion

atoms with unequal numbers of protons and electrons; they are electrically charged

• Many atoms exist only as ions in nature

• Ions are very important to biology

Negative ion

Anion

Positive ion

Cation

Valence electrons

• The outermost layer of electrons - can be predicted from periodic table

• All elements try to get a total of 8 valence electrons - the octet rule

• Valence electrons are involved in bonding

• Sharing valence electrons is a covalent bond

• Giving up an electron or gaining an electron from another atom creates ions, which can then have ionic attractions.

Covalent bonds

• Forms when atoms share electrons

• very strong

• Can be single, double, triple, or quadruple

Ionic attractions

• Form when anions and cations attract

• Can often be broken by water when dissolved

Protons + neutrons =

atomic weight/mass

Radioactive atoms

Atoms with too many particles in nucleus; so eject particles to get smaller

What can radiation cause

Burns and mutations

How does radiation cause mutations

corrupting DNA by having DNA broken and then put back together in the wrong order.

How does radiation cause burns

hitting your skin causing the molecules to move faster creating heat + burns

What are 3 names for water

1. dihydrogen monoxide

2. Water

3. H2O

What kind of bonds does water have

polar covalent bonds

Polar covalent bonds

• The electrons in the bond are shared unequally

• Gives hydrogen a slight positive charge

• Gives oxygen a slight negative charge

What bonds does water make with other water molecules

Hydrogen bonds

Hydrogen bonds

• weak attractions between two or more molecules. It is an example of inter molecular force, or IMF

• Hydrogen bonds are weak. However, many hydrogen bonds together are strong. Hydrogen bonds are important to the shape of proteins and DNA

• H-bonds are not covalent bonds. They are weak and easy to break, and they happen between two molecules, not within one molecules.

Water is Cohesive and Adhesive

• Water is highly cohesive (it sticks to itself strongly) and adhesive (sticks to other charged atoms) due to the hydrogen bonds.

• This causes capillary action and surface tension.

Capillary action

Water’s ability to travel upwards against gravity

Surface tension

The surface of water sticks together tightly resisting breaking

Water has a unique density

Water is one of the few compounds where the solid state is lighter than the liquid state.

Water has a high specific heat

• Water takes a lot of energy to heat up, but once hot it cools down very slowly

  1. Stabilizes climate, preventing large temperature changes on land especially near coasts.

  2. Temperatures in water change very little, producing less stress on aquatic life making homeostasis easy

Water can dissolve many compounds

• Waters polarity allows it to easily take apart ionic attractions so ions dissolve in water

• It can also dissolve some covalent compounds, like sugar and alcohols

What are the 5 unique/important things about water

1. Water can hydrogen bond

2. Water is cohesive and adhesive

3. Water has a unique density

4. Water has a high specific heat

5. Water can dissolve many compounds

pH

Measure of the concentration of H+ in a chemical

• High levels of H+ are found in acids, low levels of H+ in bases

Acids

Chemicals that release H+ (hydrogen ions) when dissolved in water

Bases

Chemicals that remove H+ from water. This often leaves high levels of the ion OH-. Sometimes called alkalis

pH scale

• Centered at 7

• Acids: pH values <7; the smaller, the more powerful

• Bases: pH values >7; the larger, the more powerful

• Neutral compounds have a pH of 7

• Logarithmic: each step is 10 times larger than the one before

Neutralization reaction

equal volumes of equal strength acids and bases react to form water, salt, and heat.