I. Diffusion through a Membrane
Transcript of I. Diffusion through a Membrane
Review of NYS Lab
I. Diffusion through a Membrane Big Picture Items:
The Cell Membrane & Selective Permeability: size of the molecule counts
Chemical Indicators: lab technique used to identify chemicals that are not
visible
Onion Cell: Parts of the Plant Cell & Osmosis
The Cell Membrane
3. Identify the cell membrane, cell wall, and cytoplasm in the pictures below by drawing an
arrow from the term to the appropriate place on the onion cell.
4. How can we make the cells on the left look like the cells on the right? ___________________
5. How can we make the cells on the right look like the cells on the left? ___________________
6. What makes the cell appear to shrink? _________________________________________________
7. What makes the cell appear to swell? _________________________________________________
1. Major function:
2. Other responsibilities:
Cell Membrane
Cell Wall
Cytoplasm
8. Circle the following terms if they CAN pass into or out of the cell. Place an X through the
terms that CANNOT pass into or out of the cell.
SALT PROTEINS GLUCOSE WATER
STARCH IODINE
9. When water __________________, the cell swells. When water __________________, the cell
shrinks.
10. Why? OSMOSIS
Define:
The Microscope
11. Describe how to make a wet mount slide?
12. Describe how to add a stain to a wet mount slide?
13. Were these cells observed under high or low power? ___________________ power
How can you tell?
14. Draw what these cells would look like under the other
power.
15. Some of the pain from a sore throat is caused by swelling of moist throat tissue. A
common remedy for a sore throat is to gargle (rinse the throat tissue) with salt water. Explain
why gargling with salt water would be expected to relieve the pain of a sore throat.
Using Chemical Indicators
16. How does a chemical indicator work?
17. Chemical Indicators you should know:
Indicator Original Color Color Change Substance it identifies
Benedict’s Solution Blue (Caribbean
blue)
Iodine (Lugol’s) Amber (burnt
orange/brown)
Bromothymol Blue Blue (traditional blue)
Enzyme M Indicator No color marker – no
fizz No marker – Fizz Enzyme M
18. Which indicator above requires HEAT to activate the color
change? ___________________
19. Look at the image below.
State one possible reason why molecule A could diffuse across
the membrane of the cell but molecule B could not.
_________________________________________________________________________________________
_________________________________________________________________________________________
20. Study the “initial” diagram below and predict what would happen after 20 minutes by
labeling the beaker on the right.
Initial Final
21. Explain what happened to glucose, starch, iodine and the color of the contents inside
and outside the model cell.
GLUCOSE: Size = __________________ Permeable/Impermeable? __________________
STARCH: Size = __________________ Permeable/Impermeable? __________________
IODINE: Size = __________________ Permeable/Impermeable? __________________
II. Relationships and Biodiversity Big Picture Items:
Laboratory Skills: chemical indicators, paper chromatography, gel
electrophoresis, determining amino acid sequences
Importance of Biodiversity: define term, conservation/preservation, tradeoffs
Determining Evolutionary Relationships: Using structural and molecular
evidence
Molecular Evidence Review A. Paper Chromatography
3. Use:
___________________________________________________
4. How does it differ from gel electrophoresis?
5. Describe the setup?
__________________________________________________________
__________________________________________________________
__________________________________________________________
B. Gel Electrophoresis
6. Use:
7. DNA cut with ________________________ and then
added to wells at the negative pole (because DNA is
negatively charged). Since opposites attract, DNA
will run to the _______ pole.
8. Large pieces of DNA will run ___________ than
smaller pieces.
1. Examples of structural evidence:
2. Examples of molecular evidence:
9. The more bands two specimens have in common, the more ______________ the two
specimens are to each other.
10. Circle the gel plate that contains a positive identification of the criminal?
11. Draw an arrow pointing to the band with the least amount of DNA nucleotides.
A change in hemoglobin, a protein found in red blood cells,
causes sickle-cell disease. Hemoglobin samples from different
individuals can be compared by using a specific technique. The
protein banding patterns of three samples are shown to the right.
12. Identify the technique that was used to produce these results.
_____________________________________________
13. Identify another substance that can be analyzed using this
technique.
___________________
The segments of DNA below were extracted from two different species of plants. The
segments represent the same region of DNA that codes for a particular pigment (color) in
these species.
Plant Species A: ACCGCAGGGATTCGC
Plant Species B: ACCGGAGCGATTCGC
14. A restriction enzyme is used to cut the DNA from species A and B. The enzyme binds to
the sequence G G G A T T and cuts between G and A. State how many cuts will be made in
the DNA sequences of each species when this enzyme is used.
Plant species A cuts: ____________ Plant species B cuts: ____________
C. Determining an Amino Acid Sequence
Remember, DNA (in the eukaryotic nucleus) is a code for the production of a protein within
in the ribosome of the cell. _____________ is the architect, and the ______________ are the
construction workers
15. DNA transcribed into RNA.
Adenine bonds with ___________________ Cytosine bonds with ___________________
Thymine bonds with ___________________ Guanine bonds with ___________________
16. Practice!
DNA: TAG AAA GCG GAT
mRNA: _________________________________________
A.A. Seq. _________________________________________
17. Practice again!
Triplet _________________________________________
Codon: UAC GGA CAA ACU
A.A. Seq. _________________________________________ 18. The amino acid sequences of three species shown below were determined in an
investigation of evolutionary relationships.
Based on these data, which two species are most closely related? Support your answer.
D. Enzyme M Indicator
(See Diffusion through a Membrane review sheet for more info.)
III. Making Connections Big Picture Items:
Scientific Method: designing an experiment
Interpreting data: exercise & muscle fatigue, exercise & pulse rate
Every experiment needs:
How will you remember the difference between an independent and dependent variable?
Hypothesis
_________________________________________________________________________
Constants
_________________________________________________________________________
Control Group
_________________________________________________________________________
Experimental Group
_________________________________________________________________________
Independent Variable
_________________________________________________________________________
Dependent Variable
_________________________________________________________________________
Hypothesis: Spearmint taken before an exam will increase the amount of time a student will
focus.
Control Group: ______________________________________
Experimental Grp: ______________________________________
Indep. Variable: ______________________________________
Dep. Variable: ______________________________________
Constants: ______________________________________
Sample Regents Question:
A student carried out a lab activity where she was asked to squeeze a clothespin as many
times as she could in one minute and record that number. She immediately tried the same
activity again, thinking she could do better the second time, but the number was lower. She
immediately tried again, but the number was lower still.
State one reason why she continued to get lower numbers, even though she tried to
increase the number of squeezes several times.
__________________________________________________________________________________________
Hypothesis: Rigorous exercise will increase pulse rates.
Control Group: ______________________________________
Experimental Grp: ______________________________________
Indep. Variable: ______________________________________
Dep. Variable: ______________________________________
Why should pulse rate increase with rigorous exercise?
Besides pulse rate, what other body function should increase with rigorous exercise? Explain.
IV. Beaks of Finches Big Picture Items
Concept of Natural selection: terms & application
Use of Circle o’ Finch Information
Natural Selection
What does the following mean?
“Survival of the fittest”
“Selecting agent”
Did increased competition improve or impede performance? Explain.
Know how to interpret this chart:
Sample Regents Question:
On an island populated by both warbler
finches and small tree finches, there is a
significant decrease in the amount of
animal food. Which finch population
would decrease more? Support your
answer.
Define in your own words: