Day 14 - Where'd you get those great Genes?!?!

Today we will be marking as a class:

First we will exchange and mark papers on Ohm's law. Then, we will be writing a Unit Test on Electricity. Mr. Gill will be marking it and returning it the next day. Our Biology lesson today will consist of returning and discussing correct answers from pg 124. We will then be marking our own work. We will choose select questions from the chapter review on pg 146 to mark as a class, and students will use their own judgement to decide whether or not a question is correct, partially correct, or incorrect. I will then collect these assignments from pg 146.



BLM 3-21, Ohm’s Law
1. 9.6 Ω
2. 1.3 A
3. 9.0 V
4. 0.75 A
5. 15 V
6. 30 Ω
7. (a) 5.0 A
(b) 2.5 A
8. 7.5 V



In a nutshell, Mitosis is the way cells reproduce themselves - there is no change in the total number of chromosomes at the end of this cell reproduction. Just think what would happen if we couldn't make new cells - we would never heal from even minor injuries, and we would have a really short lifespan!

Mitosis has some key concepts - Early and Late Prophase, Metaphase, Anaphase, and Telophase. Like much of biology, you have to learn the vocabulary to understand what is happening. I will be assigning pages

p. 161 - 1-5
p. 165 # 1-6 (pay very close attention to #6)
PG 184 #1- 10 from the Chapter Review.

Hint for Chapter 4 Quiz - One of the questions asks: "Which of the following organelles does not have a membrane?"

Reading Check Answers, p. 130
1. The DNA molecule is like a ladder. The sides
are made of sugar and phosphate, and the
steps of the ladder are made of four nitrogen
bases: A (adenine), G (guanine,) C (cytosine,)
and T (thymine).
2. In the DNA molecule, A always joins with T
and G always joins with C. (In a mutation in
DNA, incorrect base pairing may occur).

3. Chromatin is the material inside the nucleus
that contains DNA and proteins. Each strand
of chromatin contains one molecule of DNA.
4. Most human cells have 46 chromosomes or 23
pairs of chromosomes.
5. (a) Genes are small pieces of DNA that store
the information to make a particular protein.
(b) The genes are located at specific places on
the chromosome.
6. In retinal cells and muscle cells, only specific
genes are “read” in each cell and so only specific
proteins are made. Your retinal cells will
read certain genes and make different proteins
than your muscle cells, and different proteins
make your cells function differently.

Pg 146 # 1- 21

Checking Concepts
1. The nucleus is like a black box because there
are still unknown processes occurring and we
are not able to see all the activity that is happening
inside the nucleus.
2. DNA is required in every cell because DNA
contains the genes that code for the proteins
the cell requires to perform its functions.
3. The DNA molecule is like a ladder with the
sides of the ladder made of sugar and phosphates
and the steps of the ladder made up of
bases. The bases pair up, with G combining
with C, and A combining with T.
4. The four bases in DNA are A (adenine), G
(guanine), T (thymine), and C (cytosine).
5. The diagram should indicate the sugars and
phosphates on the sides of the ladder and the
bases correctly paired as the steps of the ladder.
6. Some functions of proteins in cells include
enzymes speeding up chemical reactions and
hormones acting as chemical messengers. In
addition, there are structural proteins, such as
the proteins in muscle, and signalling proteins,
such as antibodies.
7. (a) The parts of the cell that are involved in
making a protein for transport out of the
cell include the nucleus, the chromosomes,
the ribosome, vesicle, the endoplasmic
reticulum, the Golgi body, the nuclear
pore, RNA, and the plasma membrane.
(b) The nucleus receives a chemical signal to
make a specific protein. The nucleus contains
the chromosomes, which contain the
DNA. On the DNA are genes that carry
the message to make a particular protein.
The gene message is copied into RNA,
which leaves the nucleus through the
nuclear pores to the ribosomes. The proteins
are made on the ribosomes. If the

ribosomes are attached to the endoplasmic
reticulum, the proteins that are made
travel through the channels in the
endoplasmic reticulum and leave the
endoplasmic reticulum in vesicles. The
vesicles carry the protein to the Golgi body
where it is repackaged. Vesicles leave the
Golgi body and carry the proteins to the
cell membrane for export out of the cell.
8. The correct sequence of DNA bases is important
because, if the base sequence is incorrect,
then the correct protein will not be made or
the protein that is made will not work correctly.
The cell will be unable to do its job
well if the proteins are not working correctly.
9. The three types of gene mutation are: (a) substitution,
where one base is put in instead of
another; (b) deletion, in which a base is
removed from the sequence; and (c) insertion,
where an additional base is put into the
sequence. Substitution is the least harmful as
the same protein may be made. In deletion
and addition, a nonsense message is created
and the correct protein will not be made.
10. Gene mutations are caused by errors in the
DNA. They can be caused by mutagens, such
as viruses, cigarette smoke, radiation from X
rays and ultraviolet light, and various kinds of
chemicals in the environment. (In the next
chapter, students will learn that mutations can
also occur during mitosis and meiosis when
the DNA is getting copied.)
11. The sequence would be TGACAACA.
12. The sequence is e, a, i, c, f, h, b, d, g.
Understanding Key Ideas
13. To ensure the Spirit Bear does not become
extinct, the provincial government has limited
logging in the Great Bear Rainforest so that
the bear’s habitat is not destroyed.
14. Although there are only four bases, there are
many possible combinations of the sequences
of A, G, C, and T bases, so there are thousands
of possible messages to code for different
proteins.
15. The amount of DNA in a skin cell and the
amount of DNA is a muscle cell would be the
same because the DNA within each body cell
is identical.
16. DNA directs a cell to have a particular function
when messages are sent to the nucleus of
a cell to read certain genes and make specific
proteins. The proteins that are made and function
in that cell will determine if the cell is a
muscle cell or a stomach cell.
17. The number of chromosomes in an animal cell
or plant cell does not reflect how advanced the
organism is. Many plants have very large numbers
of chromosomes. Some amoeba have 40
or more chromosomes. A butterfly has 80
chromosomes, while humans have 46.
Chickens have 78 chromosomes. Scientists
have found that some DNA is very repetitive
in organisms.
18. If the nucleolus of a cell did not perform its
function, then ribosomes would not be made.
If ribosomes could not be made, then proteins
could not be made. The cell would not be able
to function and would die.
19. Gene therapy is still experimental, and there
are obstacles that must be overcome for gene
therapy to be successful. First, the healthy
genes must be able to enter the target cells.
Then, the healthy genes must be able to be
turned on to make the healthy proteins and
turned off when sufficient amounts of the protein
are made. During gene therapy, other
non-targeted cells may be affected, which may
cause complications.
20. Occupations that could pose greater risks of
mutations include: (a) pilots because they are
exposed to a lot of cosmic radiation; (b) construction
workers, because they are exposed to
a lot of dust and chemicals and sunlight; (c)
firefighters because they are exposed to many
toxic substances; (d) dry cleaners because they
are exposed to chemicals used to clean garments;
(e) bartenders because they are exposed
to smoke in bars; (f) farmers, because of their
exposure to pesticides and fertilizers and ultraviolet
light. Accept other possible answers, and
discuss the importance of following proper
safety precautions when working in the public
or using chemicals at home.
21. (a) The amounts of A and T are the same for
each type of cell since A pairs with T, so, if
there are 180 000 adenine bases in a piece
of DNA, the DNA should contain 180 000
thymine bases.
(b) The amount of bases is different because
these are different organisms. However,
the percentage of A=T and G=C should be
the same.
(c) The human liver and human heart sample
have the same number of chromosomes