Tuesday, May 13, 2014

Contsructed Response Tips

Today I did not get to see any of you so I sent a final prep sheet for you and the scoring guidelines for the test.  You were to finish up your open ended questions.  Since I did not get a chance to talk these through with you,I have described the main points of each question below.  I am going to have you turn those in FRIDAY so that you have them to look over before the Keystone Exam.

I also reminded you of the modules set up on Study Island for you to review.  For those that cannot log on to study island I also have paper copies of sample questions with the answers and explanations.  If you click the link below it will take you to all the possible modules.

https://www.dropbox.com/sh/kovy60zj2mkkmnz/AACfhjEe7Rz6QQCDhaHDrGFqa

Open Ended Question Advice:

Proteins are a major part of every living cell and have many different functions within each cell.  Carbohydrates also perform numerous roles in living things.
Part A:  Describe the general composition of a protein molecule
Part B:  Describe how the structures of proteins differ from the structures of carbohydrates
Part C:  Describe how the functions of proteins differ from the functions of carbohydrates.

This question is about organic molecules.  Remember that most organic macromolecules are made up of smaller subunits (known as monomers)
The subunit of Proteins are amino acids so for the first part of this answer you would want to mention that and that they are held together by peptide bonds.
Carbohydrates on the other hand are made up of simple sugars (also known as saccharides).  If you recall, the term carbohydrate literally means the Hydrate(water) of Carbon.  So it is made up of Carbon, hydrogen, and oxygen in a 1:2:1 ratio.  ANY of that information would suffice for this part of the answer
Finally, remember the different functions of proteins and carbohydrates:
            Proteins:  have a WIDE variety of functions including acting as enzymes, structural molecules, antibodies, hemoglobin and so forth.
            Carbohydrates main functions are energy and structural support (cellulose and chitin)
Using all the above information you should be able to come up with a few concise statements that adequately answer the question.

Prokaryotic cells are generally much smaller than eukaryotic cells.
A.  Identify a structural difference between prokaryotic cells and eukaryotic cells that is directly related to their difference in size.
 B.  Based on the structural difference, explain why prokaryotic cells can be much smaller than eukaryotic cells.
C.  Describe one similarity between prokaryotic cells and eukaryotic cells that is independent of size.

The BIG difference between prokaryotic cells and eukaryotic cells is that eukaryotic cells are much more complex.  They contain a nucleus and many different membrane bound organelles.  Because of this they must be much larger.  Prokaryotic cells are small simple cells that DO NOT contain membrane bound organelles or a nucleus.  Some things that they DO share in common though is that they both are encased in a cell membrane, they both contain cytoplasm, they both store DNA, they both contain ribosomes.

A.  Describe the energy transformations involved in each process
B.  Describe how energy transformations involved in photosynthesis are related to energy transformations involved in cellular respiration.

Remember that all energy originates from the sun as light energy fueled into photosynthesis.  Photosynthesis then converts energy from the sun into chemical energy in the form of glucose (remember, energy is STORED in the bonds of organic molecules.)
During cellular respiration then, the chemical energy stored in glucose is converted to another form a chemical energy in the bonds of ATP.

They are related a couple different ways.  The energy that photosynthesis puts out is also the energy that is taken into cellular respiration.

Some animals can produce a potassium ion concentration inside their cells that is twenty times greater than that of their environment.  This ion concentration gradient is maintained by the plasma membrane.
A.  Identify the process in the cell membrane that produces this difference in concentration.
B.  Explain the process that occurs as the cell produces the ion concentration gradient.
C.  Compare the process of potassium into transport to another mechanism that moves material across the plasma membrane.

First off, anytime you have molecules moving AGAINST the concentration gradient means it requires energy (in the form of ATP).  That being said we know that this occurs by active transport.  The specific type of active transport is via protein pumps that move the potassium from low to high concentration through membrane proteins.  This is different than MANY different types of other transport such as Osmosis (the movement of water) Facilitated diffusion (passive transport through proteins), endocytosis or exocytosis (movement through vesicles).  You would want to pick one of these to finish out part C.

Patau syndrome can be a lethal genetic disorder in mammals, resulting from chromosomes failing to separate during meiosis.
A.  Identify the step during the process of meiosis when chromosomes would most likely fail to separate.
B.  Describe how chromosome separation in meiosis is different from chromosomes separation in mitosis.
C.  Compare the effects of a disorder caused by chromosomes failing to separate during meiosis, such as patau syndrome, to the effects of chromosomes failing to separate during mitosis.

Some things to remember about the difference between mitosis and meiosis.  Mitosis is a form of cell division that allows our body to repair itself and grow.  It makes a genetically identical copy of itself.  The chromosomes line up at the equator, get pulled apart and you end up with the same number of chromosomes.
During meiosis though homologous chromosomes first get separated during anaphase I and then the sister chromatids get separated during anaphase II.  Any form of nondisjunction (which is what patau syndrome is caused by).  can be caused during anaphase I or II. 
If nondisjunction occurs in a cell undergoing meiosis it could potentially impact the offspring since meiosis is the formation of gametes.  If it occurred in mitosis the cells formed AFTER that would be affected but it would not be passed on to offspring.

A cattle farmer genetically crosses a cow (female) with a white coat with a bull (male) with a red coat.  The resulting calf (offspring) is roan, which means there are red and white hairs intermixed in the coat of the calf.  The genes for coat color in cattle are co-dominant.
A.  Although a farm has cattle in all three colors, the farmer prefers roan cattle over white or red cattle.  Use the punnett square to show a cross that would produce only roan offspring.
B.  Explain how a roan calf results from one white and one red-coated parent.  in your explanation, use letters to represent genes.  Be sure to indicate what colors the letters represent.
C.  Predict the possible genotypes and phenotypes of the offspring produced from two roan cattle.

Since coat color is codominant, there is no "recessive" gene so you could represent the alleles two different ways - Red with "R" and White with "W".  The more scientific way to represent them is Crand  Cw
      .  In this case either way would work.   The way to get all roan cattle is really explained to you in part B (you cross a red and a white cow/Bull)
To put this into words, how you get a roan calf is that one parent will always give a red allele, the other parent will always give a white allele therefore the offspring would be heterozygous and since coat color is codominant both would be expressed.
If you crossed to roan cattle (heterozygous) you could end up with Genotypes RR, RW, or WW which give you the phenotypes of Red, Roan ,and White respectively.

A.  Based on the data, describe a possible evolutionary relationship between rats, mice and cows.
B.  Describe how different organisms having a common gene such as COII supports the theory of evolution.
C.  The COII gene of a monkey has 203 base differences from the same gene in a rat and 210 base differences from the same gene in a mouse.  Compare the evolutionary relationships between the monkey, the rat and the mouse.

You want to look at the differences in nucleotides sequences.  The more differences there are the LESS related they would be and vise versa.   Since the genetic code is universal we are able to look at these differences and predict evolutionary relationships between organisms.  So looking at both A and C, you just take a look at which organisms have the LEAST number of differences, and you can infer that they are more related evolutionarily.

A.  Describe on limiting factor for the moose population.
B.  Explain one likely reason why the wolf population rapidly increased between 1975 and 1980
C.  Predict what will happen to the moose population's size after 1994 by describing the shape of the curve.  In your answer, be sure to explain the reasoning behind your prediction.

A limiting factor is any factor that would impact the growth of a population.  So this could be food, water, space, mates, or predators (in this case the wolves). Times when the wolf populations increased generally corresponded to times when the moose population was decreasing since they were hunting them.  The moose population at the end of this graph is VERY high so one of two things could happen, it will level out because they have reached carrying capacity.  OR it will begin to decline because there is a surplus of them for the wolves!

Hope this helps when answering the questions.
Tomorrow is my last day with you guys before the big day!!

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