quiz one Flashcards
When carrying out a controlled experiment, it is important to:
change multiple variables at once to see the full effect of the variables.
All of these choices are correct.
change only one variable at a time.
subject different groups to different conditions.
change only one variable at a time
You are working at NASA studying new life forms found in the Cueva de Villa Luz caves. You have collected an unknown specimen that appear to be 0.5 micron in size, have a cell membrane and ribosomes. This specimen could be…
a molecule
either a virus or a bacteria
a eukaryote
a virus
a prokaryote
an archea
a prokaryote
Agrobacterium is a bacterium that infects plants and causes them to form tumors. You are asked to determine how long a plant must be exposed to these bacteria to become infected. Which of the following is an appropriate CONTROL for the experiment?
Use many plants to do the experiment.
Expose the plant to Agrobacterium for only 1 minute.
Expose the plant to another concentration of Agrobacterium for different lengths of time and measure tumors formed.
Do not expose the plant to Agrobacterium and measure how many tumors are formed.
Do not expose the plant to Agrobacterium and measure how many tumors are formed
One of your friends is arguing that viruses are alive. What information would you provide to convince him that viruses can’t be considered alive?
Viruses cannot carry out metabolic reactions (use energy) on their own.
Viruses are much more closely related to archaeons than bacteria.
Viruses contain either RNA or DNA but not both.
Viruses typically have protein coats and no plasma membrane.
Viruses cannot carry out metabolic reactions (use energy) on their own
An explanation supported by a large body of observations and experimentation is referred to as a
theory
What is a covalent bond?
shared pair of electrons that holds atoms together
What is a polar covalent bond?
electrons shared unequally
What is a non polar covalent bond?
electrons shared equally
What are ionic bonds?
stealing electrons
If a solution is neutral in terms of pH, what pH is it and what makes it neutral?
pH of 7
equal number of protons (H+) and hydroxide ions (OH-)
What makes a solution more acidic?
more H+ then OH-
What makes a solution more basic?
more OH- then H+
Between polar and non polar molecules who interacts with who?
polar with polar
non polar with nonpolar
What does it mean to be hydrophilic?
water loving
polar molecules
What does it mean to be hydrophobic?
water fearing
non polar molecules
Are hydrogen bonds strong?
no very weak
continue to break and make new bonds
What is a molecule?
a group of atoms connected by covalent bonds
Which molecules are polar and non polar
C-C
C-O
C-N
O-H
C-H
nonpolar
polar
polar
polar
nonpolar
How are hydrogen bonds formed?
attraction between partially positive H atoms and partially negative atoms like O and N
What are the emergent properties of water?
cohesion + adhesion
moderates temperature change
high heat of vaporization
ice floats
What are eukaryotic cells?
cells with a nucleus
What are prokaryotic cells?
cells without a nucleus
You notice that plants in your front yard are doing better than in the back yard. You think to yourself the reason for this is probably that the front yard has better soil pH than the backyard. This is an example of a…
opinion
hypothesis
prediction
theory
hypothesis
Hypotheses are…
facts
explanations for an observation
always true
if… then statements
explanations for an observation
Compared to eukaryotes, prokaryotes are typically…
10-100 times smaller
Electronegativity of O is 3.4, C is 2.5, and H is 2.1
If this molecule was dissolved in water, which of these atoms could form hydrogen bonds with water?
1
D
D
C
C
D
Order these from least dense to most dense
cold water, warm water, ice
ice
warm water
cold water
Which axis is the dependent variable on?
y
vertical
Explain dependent variable
the part you measure
depends on the independent variable
Which axis is the independent variable on?
x axis
horizontal
What is the most common independent variable?
time
What is the difference between a hypothesis and a theory?
hypothesis can only be supported or falsified (never proven) when an overwhelming amount of data supports a hypothesis it becomes a theory
What biomolecule aids in the fundamental concept that life is membrane delimited and why?
lipids as they provide a selectively permeable barrier
What biomolecule aids in the fundamental concept that life carries and follows information?
nucleic acids store and transmit information
What is the connection between electronegativity and attraction?
more electronegative attracts more electrons
.9 difference
polar covalent
hydrophilic
Why are non polar molecules symmetrical
charges cancel and are all charged equally
Are polar molecules symmetrical?
no the charges do not cancel out as they are shared unevenly
A solution of pH 5 contains _____ H+ then a solution at pH 3
100 times less
The H+ of a solution changes from .000001 to .000000001. Did the pH increase or decrease? What did the pH change to?
increased to 9
You have a solution with a hydrogen ion concentration of .000001. What is the pH of the solution?
6
The element carbon (C) has an atomic number of 6. An atom of C has ___ protons and ___ electrons. The valence shell is shell ___ and contains ____ electrons. C will typically make
___ bonds.
6
6
2
4
4
How many hydrogen atoms are present in a hydrocarbon chain of five carbons joined to each other by single covalent bonds?
12
The biochemical reaction used to make chains of biological polymers and involves the removal of water molecule is called…..
dehydration synthesis
