Biology Test 1
Terms
- What is the age of the Earth?
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4.5 Billion Years
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How long have cells been on this planet?
- 3.8 billion years
- How might life have originated on earth?
- Spontaneously
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What properties dif the first cells have?
- The could store and replicate genetic information & a membrane surrounded its molecule.
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What impact did photosynthesis have on life on land?
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The oxygen levels rose in the atmosphere causing many organisms to disappear.
The ozone layer was formed.
The ozone layer protected the planet by absorbing some of the UV radiation, making it possible for life to more to land.
- What is the advantage of multicellularity?
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Division of labor is possible and cells take on unique functions.
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What are the six kingdoms in which organisms are divided?
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- Bacteria
- Archaea
- Animals
- Plants
- Fungi
- Protista
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What kingdoms are prokaryotes?
What kingdoms are eukaryotes?
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- Prokaryotes
- Bacteria, Archaea
- Eukaryotes
- Animals, Plants, Fungi, Protista
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What particls make up atoms?
What are their charges and where do they reside?
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Protons: +1 charge, nucleus
Neutrons: 0 charge, nucleus
Electrons: -1 charge, float around the nucleus
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How many types of atoms make up an element?
By how many letters (symbols) is each element designated in the periodic table?
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One type of atom makes up each element.
Each element has a 1 or 2 letter symbol.
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When referring to electrons, what is an orbital?
At most how many electrons can occupy and orbital?
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The area around the nucleus where an electron can be found with 90% certainty at any given time.
2 electrons at most can occupy an orbital.
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What makes an atom stable?
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Filling the outermost shell with as many electrons as it can hold.
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What is a chemical bond?
What four types of bonds were discussed in class?
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Chemical force that links atoms together to form molecules.
- ionic bond
- covalent bond
- polar covalent bond
- Hydrogen bond
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What is a ionic bond?
Provide an example.
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Forms between ions, which occur when atoms gain or lose an electron.
Sodium chloride (NaCl) - table salt
*opposite charges attract
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What is a covalent bond?
Provide an example.
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A bond between atoms sharing a pair of electrons to fill their outer shell.
two hydrogens - Hydrogen gas
Carbon bonded to 4 hydrogen to form methane gas
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How may pairs of electrons are shared in a single covalent bond?
Double covalent bond?
Triple covalent bond?
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- One
- Two - ethylene (plant stress hormone)
- Three - Nitrogen gas
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What is a polar covalent bond?
Provide an example.
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Shared electrons prefer one atom ore than the other.
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What is a hydrogen bond?
Provide an example.
Is this a strong or weak bond?
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Occur between polar covalently bonded atoms.
Water
Very weak
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What is a chemical reaction?
- Making & breaking of chemical bonds.
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In pure water,what is the level of H+ compared to OH?
Is the solution neutral?
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They are equal.
Yes, the solution is neutral.
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What occurs to the pH of pure water if HCl is added?
What if NaOH is added?
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Makes the solution acidic
Makes the solution basic
- What pH values indicate acidity versus basicness?
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pH 1 up to 7 = acidic
above 7 to 14 = basic
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What is a functional group?
What are the five functional groups that were presented in class?
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Consist of a set of atoms that are part of a larger molecule & have defined set of properties.
- carboxyl group
- hydroxyl group
- amino group
- phosphate group
- sulfydryl group
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What are four types of macromolecules in cells?
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- Proteins
- Carbohydrates
- Nucleic Acid
- Lipids
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What is a condensation reaction?
Hydrolysis reaction?
Which releases energy and which costs energy?
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Removes a water molecule to build (requires energy)
Uses a hydrogen to break a bond (releases energy)
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What is the function of carbohydrates in cells?
What is their basic formula?
What is an example of a monosaccharide, disaccharide, polysaccharide?
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Energy source, structural component of the cell
CH20
glucose, Lactose, Cellulose or glycogen
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What is the function of proteins in cells?
- Movement, enzymes, structural component of cell, defense against disease, communication
- How many different amino acids exist in a cell?
- 20 different types
- What are the four levels of organization of a protein structure?
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primary
secondary
teritiary
quaternary
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What is the function of nucleic acids?
- storage & release of informaton
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What are the two types of nucleic acids?
What are their building blocks?
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DNA (adenine, cytosine, guanine, thymine)
RNA (adenine, cytosine, guanine, uracil)
Nucleotides (phosphate group, sugar, and a base)
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What is the function of DNA?
RNA?
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DNA stores information
RNA is copied from DNA to serve as a template to make proteins
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What are the three parts of a nucleotide?
What is the sugar in DNA versus RNA?
Which is double stranded? Which is single stranded?
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Sugar, phosphate group, and a base
Deoxyribo (DNA) - double stranded
Ribo (RNA) - single stranded
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What properties are shared by all lipids?
What are the functions of lipids is cells?
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Water insoluable, non-polar, chemically diverse, hydrophobic, lipids associate with one another
Structural component of cells (membranes)
Energy storage (fats & oils)
communication among cells
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What are fats and oils composed of?
What is their main function?
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Made of triglycerides (glycerol and three fatty acids)
Energy storage
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What are phospholipids composed of?
What is their main function?
Why do phospholipids spontaneously form bilayers in water?
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Fatty acids bonded to a glycerol, but one fatty acid is replaced by a phosphate-containing compound.
Phospholipid bilayers
The heads are hydrophilic and the tails are hydrophobic.
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What are possible roles for steroids in cells?
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Signaling molecules
part of cell membranes
- What is the size range for cells?
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1 - 100 micrometers
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Why is there a size limitation to cells?
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As the volume increases their surface area doesn't increase at an equal rate.
They need to exchange materials with the environment.
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Please describe he structure of a prokaryotic cell.
What kingdoms contain organisms that have cells of this type?
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*Small (1-10 micrometers) *Simple *No nucleus *DNA is present in the nucleoid *Plasma membrane surrounds cytoplasm *Ribosomes *Bioch
- What are the overall characteristics of eukayotic cells?
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*Larger & more complex
*plasma membrane, cytoplasm & ribsomes
*Also many membrane bound compartments, cytoskeleton, nucleus, and many other organelles