Download Study Guide for Test on Chapter Five

Study Station 1: Macromolecules
A macromolecule is a very large molecule made up of smaller units called
monomers. Macromolecules are formed by dehydration synthesis in which water
molecules are removed to form bonds. There are four major macromolecules:
carbohydrates, lipids, proteins, and nucleic acids. Carbohydrates are commonly
called sugars aka saccharides. When iodine is placed in a carbohydrate solution,
the iodine will turn from yellow to black. Lipids include the fatty acids, oils, and
waxes. They can be saturated or unsaturated. Proteins are made from chains of
amino acids. There are 20 different amino acids. Lastly, DNA and RNA are our
nucleic acids. DNA is double stranded while RNA is single stranded. Both carry
genetic information of our cells.
Practice Question 1:
A student filled two Petri dishes with a clear cornstarch gel, then marked the
letter “X” invisibly onto the gel in Petri dish 1 with a damp cotton swab. He then
placed saliva from his mouth onto a second cotton swab and used that swab to
mark the letter “X” invisibly onto the gel in Petri dish 2.
Fifteen minutes later, he rinsed both Petri dishes with a dilute solution of iodine to
indicate the presence of starch. The surface of Petri dish 1 turned completely
blue, indicating starch. Most of the surface of Petri dish 2 was blue, except the
letter “X” was clear, as shown above.
The most probable explanation of the clear “X” is that
A
B
C
D
the starch in the gel was absorbed by the damp cotton swab.
the iodine reacted with a chemical in the saliva and broke down.
a chemical in the saliva broke down the starch in the gel.
the saliva prevented the iodine from contacting the starch in the gel.
Study Station 2: Cell/Plasma Membrane
When you think about a membrane, imagine it is like a big plastic bag with some tiny holes.
That bag holds all of the cell pieces and fluids inside the
cell and keeps any nasty things outside the cell. The
holes are there to let some things move in and out of
the cell. Thus, the cell membrane is semi-permeable.
The cell membrane is not one solid piece. Everything in
life is made of smaller pieces and a membrane is no
different. Compounds
called proteins and phospholipids make up most of
the cell membrane. The phospholipids make the basic
bag. The proteins are found around the holes and help
move molecules in and out of the cell.
Scientists describe the organization of the
phospholipids and proteins with the fluid mosaic
model. That model shows that the phospholipids are in
a shape like a head and a tail. The heads like water
(hydrophilic) and the tails do not like water
(hydrophobic). The tails bump up against each other
and the heads are out facing the watery area
surrounding the cell. The two layers of cells are called
the bilayer.
Practice Question 2a:
The cell membrane of the red blood cell will allow water, oxygen, carbon dioxide,
and glucose to pass through. Because other substances are blocked from
entering, this membrane is called
A
B
C
D
perforated.
semi-permeable.
non-conductive.
permeable.
Practice Question 2b:
The plasma membrane of a cell consists of
A protein molecules arranged in two layers with polar areas forming the outside
of the membrane.
B two layers of lipids organized with the nonpolar tails forming the interior of the
membrane.
C lipid molecules positioned between two carbohydrate layers.
D protein molecules with polar and nonpolar tails.
Study Station 3: Proteins and Enzymes
Proteins are made of monomers called amino acids. There are 20 amino acids
that exist. The sequence and different amounts of amino acids makes proteins
different from each other. Enzymes are a type of proteins that catalyze (i.e.
increase the rates of) chemical reactions. In enzymatic reactions, the molecules
at the beginning of the process are called substrates, and the enzyme converts
them into different molecules, the products. Enzymes are extremely selective
and work like a “lock and key.” Enzymes will work slowly in cold temperatures.
They will also denature (deform) in extremely hot temperatures and extreme
acidity or basicity.
Practice Question 3:
Some snake venoms are harmful because they contain enzymes that destroy
blood cells or tissues. The damage caused by such a snake bite could best be
slowed by
A applying ice to the bite area.
B drinking large amounts of water.
C inducing vomiting.
D increasing blood flow to the area
Study Station 4: Prokaryotes vs Eukaryotes
Prokaryotic cells, like bacteria, have no nuclei, while eukaryotic cells (animals,
plants, fungi) do have true nuclei.
Despite their apparent differences, these two cell types have a lot in common.
They perform most of the same kinds of functions, and in the same ways. Both
are enclosed by plasma membranes, filled with cytoplasm, and loaded with small
structures called ribosomes. Both have DNA which carries the archived
instructions for operating the cell.
Despite all of these similarities, the differences are also clear. Eukaryotic cells
are much larger and much more complex than prokaryotic cells.
If we take a closer look at the
comparison of these cells, we see
the following differences:
1. Eukaryotic cells have a true
nucleus, bound by a double
membrane. Prokaryotic cells
have no nucleus.
2. Eukaryotic DNA is linear;
prokaryotic DNA is circular (it
has no ends).
3. The cytoplasm of eukaryotic
cells is filled with a large, complex collection of organelles, many of them
enclosed in their own membranes; the prokaryotic cell contains no
membrane-bound organelles which are independent of the plasma
membrane.
Practice Question 4:
Eukaryotic cells are differentiated from prokaryotic cells because eukaryotic cells
A are much smaller.
B have permeable membranes.
C have a higher rate of reproduction.
D have nuclei.
Study Station 5: Eukaryotic Organelles
Below is a list of organelles that are commonly found in eukaryotic cells, which are
found in plant, animal, and fungi cells.
Organelle
Function
Nucleus
The “brains” of the cell, the nucleus directs cell activities and
contains genetic material called chromosomes made of DNA.
Mitochondria
Ribosomes
Make energy out of food
Make protein
Golgi Apparatus Make, process and package proteins
Lysosome
Contains digestive enzymes to help break food down
Endoplasmic
Reticulum
Called the "intracellular highway" because it is for transporting
all sorts of items around the cell.
Vacuole
Used for storage, vacuoles usually contain water or food. (Are
you are thirsty? Perhaps your vacuoles need some water!)
Plant cells also have:
Chloroplasts
Use sunlight to create food by photosynthesis
Cell Wall
For support
Practice Question 5:
Which cellular organelle is
responsible for packaging the
proteins that the cell secretes?
A cytoskeleton
B cell membrane
C lysosome
D Golgi apparatus
Study Station 6: DNA
DNA stands for deoxyribonucleic acid and is one of the two types of nucleic
acid found in our cells. The name describes what the molecule is. DNA is:


A Nucleic Acid (i.e. it is made up of strings of nucleotides bonded
together)
Has a backbone made of phosphate and deoxyribose
DNA is a record of instructions telling the cell what its job is going to be. A good
analogy for DNA as a whole is a set of
blueprints for the cell, or computer code
telling a PC what to do. It is written in a
special alphabet that is only four letters long!
Unlike a book or computer screen, DNA isn't
flat and boring - it is a beautiful curved
ladder. We call this shape a double helix.
The letters of the DNA alphabet
(called bases) make up the rungs, special
sugars and other atoms make up the
handrail.
The rungs are very special. Each one has a name, but they prefer to be called by
their initials: A, T, C and G They do not like to be by themselves so always pair
up with a friend. But they are very choosy about their friends:

A and T are best friends and always hang out together

G and C are best friends and always hang out together
Practice Question 6:
Which of the following base pair sequences could be produced in DNA
replication?
A
5' AGTCUT 3'
3' TCUGTA 5'
B
5' AGTCAT 3'
3' TCAGTA 5'
C
5' AGTCAT 3'
3' CTGACG 5'
D
5' AGTCAT 3'
3' UCAGUA 5'
Study Station 7: Central Dogma Protein Synthesis
Steps in Protein Synthesis:
STEP 1: The first step in protein synthesis is the transcription of mRNA from a DNA gene
in the nucleus. The mRNA migrates from the nucleus into the cytoplasm. The mRNA
goes to a ribosome, which is either free floating in the cytoplasm or attached to the
rough endoplasmic reticulum.
In the cytoplasm, protein synthesis is actually initiated by the AUG codon (3 nucleotides)
on mRNA. The tRNA which initiates the protein synthesis has the amino acid methionine
attached. The process continues with the next codon. The amino acid chain will attach
together to make a polypeptide (a protein).
Practice Question 7:
5' ATCAGCGCTGGCGGT 3'
The above sequence of DNA is part of a gene. How many amino acids are
coded for by this segment?
A) 5
B) 8
C) 10
D) 20
Study Station 8: Mitosis
Mitosis is the process by which a eukaryotic cell separates the chromosomes in its cell
nucleus into two identical sets, in two separate nuclei. It is generally followed
immediately by cytokinesis, which divides the nuclei, cytoplasm,organelles and cell
membrane into two cells containing roughly equal shares of these cellular components.
Mitosis and cytokinesis together define the mitotic (M) phase of the cell cycle—
the division of the mother cell into two daughter cells, genetically identical to each other
and to their parent cell. There are 4 phases of mitosis: prophase, metaphase, anaphase,
and telophase. This accounts for approximately 10% of the cell cycle. In mitosis, the
starting cell is diploid; it has 2 sets of DNA (one from the egg and one from the sperm).
In the end of this cell cycle, the daughter cells are also diploid. So 2n (2 sets of DNA) 
2n (2 sets of DNA).
Practice Question 8:
Which of the following sequences represents chromosome
number during mitosis?
A) n + n  2n
B) 2n  2n
C) n  n
D) 2n  n
Study Station 9: Meiosis
Meiosis is a special type of cell division necessary for sexual reproduction in eukaryotes.
The cells produced by meiosis are gametes or spores. In many organisms, including
all animals andland plants (but not some other groups such as fungi), gametes are
called sperm and egg cells.
The outcome of meiosis is four (genetically unique) haploid cells, compared with the
two (genetically identical) diploid cells produced from mitosis. Meiosis begins with one
diploid cell containing two copies of each chromosome—one from the organism’s
mother and one from its father—and produces four haploid cells containing one copy of
each chromosome. Each of the resulting chromosomes in the gamete cells is a unique
mixture of maternal and paternal DNA, resulting in offspring that are genetically distinct
from either parent. This gives rise to genetic diversity in sexually reproducing
populations.
Practice Question 9:
Which of the following statements correctly describes meiosis?
A) Cells divide only once during meiosis.
B) Meiosis does not occur in reproductive cells.
C) The cells produced at the end of meiosis are genetically identical to the
parent cell.
D) The cells produced at the end of meiosis contain half the number of
chromosomes as the parent cell.
Study Station 10: Genetics
DNA is wrapped together to form structures called chromosomes. Most cells in the
human body have 23 pairs of chromosomes, making a total of 46. Individual sperm and
egg cells, however, have just 23 unpaired chromosomes. You received half of your
chromosomes from your mother's egg and the other half from your father's sperm cell. A
male child receives an X chromosome from his mother and a Y chromosome from his
father; females get an X chromosome from each parent.
Genes are sections or segments of DNA that are carried on the chromosomes and
determine specific human characteristics, such as height or hair color. Because you have
a pair of each chromosome, you have two copies of every gene (except for some of the
genes on the X and Y chromosomes in boys, because boys have only one of each).
Heredity is the passing of genes from one generation to the next. You inherit your
parents' genes. Heredity helps to make you the person you are today: short or tall, with
black hair or blond, with brown eyes or blue.
Genes can be either dominant or recessive. Dominant genes show their effect even if
there is just one mutation in one copy of that gene pair; the one mutation "dominates" the
normal back-up copy of the gene, and the characteristic shows itself.
A person can be born with gene mutations, or they can happen over a lifetime. Mutations
can occur when cells are aging or have been exposed to certain chemicals or radiation.
Fortunately, cells usually recognize these types of mutations and repair them by
themselves. Other times, however, they can cause illnesses, such as some types of cancer.
If the gene mutation exists in egg or sperm cells, children can inherit the gene mutation
from their parents. When the mutation is in every cell of the body (meaning a child was
born with it), the body is not able to "repair" the gene change.
Study Station 11: Punnett Squares
One of the easiest ways to calculate the mathematical probability of inheriting a
specific trait was invented by an early 20th century English geneticist named
Reginald Punnett. His technique employs what we now call a Punnett square.
This is a simple graphical way of discovering all of the potential combinations of
genotypes that can occur in children, given the genotypes of their parents. It also
shows us the odds of each of the offspring genotypes occurring.
Setting up and using a Punnett square is quite simple once you
understand how it works. You begin by drawing a grid of
perpendicular lines:
Next, you put the genotype of one parent across the top and that of
the other parent down the left side. For example, if parent pea plant
genotypes were YY and yy respectively,
the setup would be:
y
Note that only one letter goes in each box for the parents. It
does not matter which parent is on the
side or the top of the Punnett square.
Next, all you have to do is fill in the boxes by copying the row and
column-head letters across or down into the empty squares. This gives us the
predicted frequency of all of the potential genotypes among the offspring each
time reproduction occurs. Remember, homozygous means you have the same
alleles from each parent (AA or aa). Heterozygous means you received different
alleles from your parent (Aa).
y
Biology Review for Final:
Stations
Directions:
1. You have eight (8) minutes at each station before
rotating.
2. Read the paragraph of information at the station.
3. Summarize the information on your own paper following the instructions
below.
4. Answer the practice question for that station.
5. Rotate to the next station and perform steps “a-d” again.
For Each Station:
a) Write the station name down
b) Summarize the important points of the information provided. Use bullet
points.
c) What is the answer to the multiple choice question?
d) What is the evidence that proves your answer is right? (It is okay to quote
a sentence from the information)
Biology Review for Final:
Stations
Directions:
1. You have eight (8) minutes at each station
before rotating.
2. Read the paragraph of information at the
station.
3. Summarize the information on your own paper following the
instructions below.
4. Answer the practice question for that station.
5. Rotate to the next station and perform steps “a-d” again.
For Each Station:
a) Write the station name down
b) Summarize the important points of the information provided. Use bullet
points.
c) What is the answer to the multiple choice question?
d) What is the evidence that proves your answer is right? (It is okay to
quote a sentence from the information)