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Reporting Category 1: Cell Structure and Function
B.5 The student knows how an organism grows and the
importance of cell differentiation.
(A) describe the stages of the cell cycle, including
deoxyribonucleic acid (DNA) replication and mitosis,
and the importance of the cell cycle to the growth of
organisms.
CELL CYCLE
Eukaryotes’ have a cell cycle which consists of
Interphase
Four Phases:
1. G1:
2. S:
3. G2:
4. M:
INTERPHASE- S PHASE:
DNA REPLICATION
Before a cell divides, it duplicates its DNA in a copying process
called replication. This process, which occurs in the S phase of
interphase of the cell cycle, ensures that each resulting cell has
the same complete set of DNA molecules.
DNA helicase:
DNA polymerase:
M PHASE
The M phase of the cell cycle, which follows interphase, produces
two daughter cells. The M phase takes its name from the processes
of mitosis. During the normal cell cycle, interphase can be quite
long. In contrast, the process of cell division usually takes place
quickly.
The M phase occurs in two main stages.
• The first stage of the process, division of the cell nucleus is called
mitosis.
• The second stage, the division of the cytoplasm, is
called cytokinesis.
4 STAGES OF MITOSIS
P
M
A
T
Source: Drawing adapted from Mitosis, Dr.
Martin Huss, Arkansas State
CYTOKINESIS
As a result of mitosis, two nuclei each with a duplicate set
of chromosomes are formed. All that remains to complete
the M phase of the cycle is cytokinesis, the division of the
cytoplasm. Cytokinesis usually occurs at the same time as
telophase.
Once cytokinesis is complete two new daughter cells are
formed. Each new daughter cell will enter into interphase.
One division
2n  2n
(same number of
chromosomes)
Results in 2 genetically
identical cells
MITOSIS VS. MEIOSIS
Mitosis
Produces body cells(Somatic cells
for growth and repair)
Daughter cells diploid(2N)
Two daughter cells produced
In metaphase chromosomes line up
singly
One nuclear division
Daughter cells have two sets of
chromosomes(pairs)
Daughter cells are genetically
identical to the parent cell
Insures that all daughter cells are
genetically identical
Meiosis
• Produces sex cells(Gametes for
sexual reproduction)
• Daughter cells haploid(N)
• Four daughter cells produced
• In metaphase I chromosomes line
up as homologous pairs
• Two nuclear divisions
• Daughter cells have only one
member of each pair of
chromosomes
• Daughter cells have one-half of
the genes from the parent cell
• Generates genetic diversity
through crossing over and random
separation of homologous pairs of
chromosomes
Reporting Category 2: Mechanisms of Genetics
The student will demonstrate an understanding of the
mechanisms of genetics.
(B.6) Science concepts. The student knows the
mechanisms of genetics, including the role of nucleic
acids and the principles of Mendelian Genetics. The
student is expected to
(A) identify components of DNA, and describe how
information for specifying the traits of an organism is
carried in the DNA;
DNA
DNA is a polymer of nucleotides.
A nucleotide is made up of three parts: a
sugar, a phosphate and one of four bases
In DNA, the bases are A, T, C, and G
DNA’s shape is a double helix
The two strands are held together by
HYDROGEN bonds
A binds to T
C binds with G
DNA REPLICATION
• Process of DNA copying itself
• Steps
• DNA Unzips (Hydrogen bonds break)
• Each side acts as a template
• New DNA nucleotides are added according to basepairing rules
• Two new molecules of DNA result – each with one old
and one new strand.
• Happens in INTERPHASE (before mitosis or meiosis)
PROTEIN SYNTHESIS
Remember, genes are made of DNA and are in the nucleus
Genes (DNA) contain the instruction for making a protein
In transcription, DNA is used to make mRNA in the nucleus
mRNA then leaves the nucleus and goes to the ribosome
In translation, tRNA then brings amino acids in the proper
order to make the protein on the ribosome.
Made of amino acids
DNA  mRNA  protein
CAN YOU IDENTIFY THE PARTS?
1. DNA
2. mRNA
3. Nucleus
4. Cytoplasm
5. Ribosome
6. Codon
7. Anticodon
8. tRNA
9. Amino acid
10. Protein (polypeptide)
READING THE CODON CHART
Be sure to use mRNA
You won’t have to
memorize this!
What amino acid is
coded for by the DNA
ATA GAG
First convert DNA to mRNA
ATA GAG
UAU CUC
UAU = tyr
CUC = Leu
GENETICS
This diagram shows the cross
between 2 heterozygous
purple flowers
Cross is:
Bb x
Bb
Notice that 75% are purple and
25% white
We have two genes for each trait – this is our GENOTYPE
One gene came from mom, one from dad
If the genes are alike, the individual is homozygous (RR, rr)
If the genes are different , they are heterozygous (Rr)
Some genes are dominant and others are recessive
We only show a recessive trait if we have no dominant gene
RR and Rr would “look” dominant
rr would look recessive
GENETIC TECHNOLOGY
TRANSGENIC ORGANISMS
Organisms that have 2
different kinds of DNA
DNA FINGERPRINTING
Gene cloning
Use gel electrophoresis
to compare DNA
fragments
Uses bacteria to make
human proteins like
insulin
IF DNA matches, it’s
from the same
individual
Evidence points
to suspect 2
Reporting Category 1:Cell Structure and Function
B.5 The student knows how an organism grows and the
importance of cell differentiation.
(C) describe the roles of DNA, ribonucleic acid (RNA),
and environmental factors in cell differentiation.
DNA
What is the basic structure of DNA?
What are the building blocks of DNA?
What are the parts of a nucleotide?
The sides of the DNA ladder are made up of what 2 alternating
molecules?
What does it mean to have anti-parallel strands?
What makes up the steps or rungs of the ladder?
What is special about the order of the nitrogen bases?
What are the 4 nitrogen bases?
According to the base pairing rules adenine always pairs with
__________ .
What type of bond hold the nitrogen bases together?
DNA VOCABULARY REVIEW
BUILDING A DNA MODEL
Match the
nucleotides on
the far right with
the nucleotides
in the box to
complete the
DNA strand.
Adenine - Thymine
Guanine - Cytosine
PROTEIN SYNTHESIS
Genes carry the information needed by cells to produce
proteins, and proteins determine traits such as coloration.
So how are proteins made?
Protein synthesis is the process in which cells build
proteins. There are 2 main steps in protein synthesis,
transcription and translation.
In transcription segments of DNA serve as template to
produce complementary mRNA molecules.
In translation the code carried by mRNA is fed into a
ribosome "machine" and causes specific amino acids to be
linked together to form a protein.
TRANSCRIPTION
In eukaryotic cells, mRNA is produced in the cell’s nucleus
and moves to the cytoplasm to play a role in the production
of proteins. Transcription requires an enzyme, known
as RNA polymerase is similar to DNA polymerase.
bonds A-U (Uracil not Thymine) and C-G
The genetic code is read three “letters” at a time so that
each “word” is three bases long and corresponds to a
single amino acid. Each three letter word is called a codon.
TRANSLATION
The sequence of nucleotide bases in an mRNA molecule is
a set of instructions that gives the order in which amino
acids should be joined to produce a polypeptide. Once the
polypeptide is complete, it then folds into its final shape or
joins with other polypeptides to become a functional
protein.
Translation uses another type of RNA known as tRNA.
Each tRNA molecule carries just one kind of amino acid. In
addition, each tRNA molecule has three unpaired bases,
called the anticodon
AMINO ACID CHART
PUTTING IT ALL TOGETHER
DNA / RNA
Carry genetic information
Made of a chain of nucleotides
Nucleotides contain a sugar, phosphate, and a nitrogen
base
DNA / RNA
DNA
RNA
Double stranded
Single stranded
“Double Helix”
Four base pairs:
Four base pairs: ATGC
Sugar is Deoxyribose
Found in nucleus
AUCG
Sugar is Ribose
BASE PAIR RULE
In DNA,
Adenine always pairs with Thymine, and
Guanine always pairs with Cytosine
REPLICATION
Making of an identical
strand of DNA
“semi” conservative
CENTRAL DOGMA
DNA  RNA  protein  trait
TRANSCRIPTION
DNAmRNA
Occurs in nucleus
Complementary
mRNA strand is
produced from a
segment of DNA
TRANSLATION
Connects amino acids in the correct order to make a protein
Occurs in the cytoplasm within the ribosomes
A- amino acid
B- tRNA
C- anticodon
D- codon
E- mRNA
F- Ribosome
G-polypeptide
CODON
Sequence of three mRNA nucleotides that code for an amino
acid
MUTATIONS
Change in DNA code
May cause a change in protein produced
NOT always harmful
Sickle Cell Mutation
When DNA is extracted from the red algae Polyides
rotundus, 32% of the nitrogen bases are guanine.
Based on this information, what percentage of the
bases are most likely adenine?
A. 9%
B. 18%
C. 36%
D. 64%
Charles A. Dana Center Science TEKS Toolkit www.sciencetekstoolkit.org
The genetic instructions for an organism are
contained in the DNA molecule. The instructions for a
specific organism are determined by the —
A. number of nucleic acids in the DNA molecule
B. length of the DNA molecule
C. sequence of the nitrogen bases in the DNA
molecule
D. type of nitrogen bases in the DNA molecule
Charles A. Dana Center Science TEKS Toolkit www.sciencetekstoolkit.org
The flow of information during gene expression is —
Charles A. Dana Center Science TEKS Toolkit www.sciencetekstoolkit.org
The amino acid sequence methionine, tryptophan, and
aspartic acid is coded by which set of DNA bases?
A. AUGUGGGAU
B. TTCTCCCTT
C. UACACCGUA
D. TACACCCTA
Charles A. Dana Center Science TEKS Toolkit www.sciencetekstoolkit.org
The genes of an organism control all its biological
processes by controlling the
A. sequence of nitrogen bases in a DNA molecule
B. synthesis of proteins in each cell
C. number of chromosomes in each cell
D. type of nitrogen bases in a DNA molecule
Charles A. Dana Center Science TEKS Toolkit www.sciencetekstoolkit.org
For a mutation to be evolutionarily significant it—
A. changes the type of protein being produced
B. has a neutral effect on an organism
C. provides an advantage to the species
D. causes the loss of a gene
Charles A. Dana Center Science TEKS Toolkit www.sciencetekstoolkit.org
The DNA strand TAGTTGTTTTGC codes for the amino acid
sequence isoleucine, aspartic acid, lysine, and threonine.
If a point mutation takes place in the DNA, and the first triplet
becomes TAT, what effect will this have on the amino acid
sequence?
A. The first amino acid in the sequence remains isoleucine.
B. Isoleucine is replaced by methionine in the amino acid
sequence.
C. The amino acid sequence now includes lysine.
D. The last amino acid in the sequence will become serine.
Charles A. Dana Center Science TEKS Toolkit www.sciencetekstoolkit.org
Approximately 900 people live in the small isolated village of
Limone in northern Italy. About 40 of the villagers have high
levels of the bad blood cholesterol and low levels of the good
cholesterol.
suffer
novillage
harmful
effects.
Doctors
Approximately
900However,
people live in they
the small
isolated
of Limone
in northern
Italy. About
40
of the found that these villagers produce a protein that is efficient
have
villagers have high levels of the bad blood cholesterol and low levels of the good cholesterol.
at clearing the bad type of cholesterol from arterial plaque and
However,
moving
to the
liver.Doctors
Which
offound
the that
following
bestproduce
explains
thisthat
thy
suffer no it
harmful
effects.
have
these villagers
a protein
isphenomenon?
efficient at
clearing the bad type of cholesterol from arterial plaque and moving it to the liver. Which of
the following
A. explains
The villagers
take vitamin and mineral supplements.
best
this phenomenon?
A.B.
TheThere
villagersare
takechemicals
vitamin and mineral
supplements.
in the
water that flush out the cholesterol.
B. There are chemicals in the water that flush out the cholesterol.
C. The villagers eat a diet consisting mostly of meat and cheese.
C. The villagers eat a diet consisting mostly of meat and cheese.
There
is a mutation
inofthe
genes
of some villagers.
D.D.
There
is a mutation
in the genes
some
villagers.
Charles A. Dana Center Science TEKS Toolkit www.sciencetekstoolkit.org
During cell division, if a chromosome breaks, a mutation
occurs. Which of the following processes prevent or
minimize chromosome breakage during cell division?
A The chromosomes tightly coil before the nucleus divides.
B. Protein synthesis takes place during the division of the
cytoplasm.
C. Hydrogen bonds form between nitrogen bases.
D. An enzyme rearranges the nitrogen bases in a gene.
Charles A. Dana Center Science TEKS Toolkit www.sciencetekstoolkit.org
A photomicrograph of onion root tip cells during mitosis is shown below.
A photomicrograph of onion root tip cells during mitosis is shown below.
© iStockphoto.com/Alan John Lander Phillips
Which phase of mitosis is occurring in the cell indicated by the arrow?
F Prophase
G Metaphase
H Anaphase
J Telophase
© iStockphoto.com/Alan John Lander Phillips
Which phase of mitosis is occurring in the cell indicated by the arrow?
F Prophase
G Metaphase
H Anaphase
J Telophase
A model of a DNA molecule is shown below.
The arrow indicates —
F the bond between adjacent phosphate and deoxyribose molecules
G the junction of introns and exons in the sense strand of DNA
H the hydrogen bond between complementary nucleotides
J the junction of a codon and a DNA triplet
Characteristics such as a widow’s peak or attached
earlobes are determined by the genetic code. Which
components of DNA are referred to as the genetic
code?
F Phosphate groups
G Nitrogenous bases
H Deoxyribose sugars
J Hydrogen bonds
In a DNA, the letters A, T, C, and G represent
A
B
C
D
bases.
sugars.
proteins.
amino acids.
The corresponding amino acids are brought into a
cell's ribosome by which type of RNA?
A
B
C
D
messenger RNA
ribosomal RNA
transfer RNA
replication RNA
Which of these must occur during S phase of the cell
cycle so that two daughter cells can be produced
during M phase?
A The DNA must be replicated.
B The chromosomes must be joined.
C The cytoplasm must be separated.
D The cell membrane must be expanded
The diagram below represents the cell cycle.
When cells leave the cell cycle, they exit during G1 phase and
then enter G0 phase, a resting period. Most normal cells can
leave G0 phase and reenter the cell cycle at G1 phase before
entering S phase. Cancer cells are different because they
cannot enter G0 phase and are likely to do which of the
following?
A Fail to complete S phase C Repeat the cell cycle continuously
B Mutate during G phase D Die after completing mitosis
The _____ contains spindle fibers, centrioles, and
aster fibers.
A spindle apparatus
B centromere
C chromosome
D nuclear envelope
What phase of cell division comes immediately after
the phase shown below?
A cytokinesis
B prophase
C cyclin phase
D anaphase
Which of these events does not occur during
telophase?
A
B
C
D
chromosomes arrive at cellular poles
cytoplasm splits in two
chromosomes relax
spindle apparatus disassembles
What structures are lined up at the center of this cell?
A cyclins
B single chromatids
C chromosomes
D kinases