Quiz #10 (100 pts.)
1. During which phase of CELL Cycle does DNA synthesis occur?
2. During which phase of cell division does the chromosomes condense and become visible?
3. The phase of cell division where the chromosomes align along the central p
How Do Genes Interact?
Epistasis occurs when the alleles of one gene cover up or alter the expression of alleles of another
gene; that is, the phenotypic expression of one gene is affected by another gene.
An example is coat color in Labrador retrievers.
How Is DNA Replicated?
Three modes of DNA replication appeared possible
Three years after Watson and Crick published their structure of DNA, the American biochemist
Arthur Kornberg demonstrated that the DNA molecule contains the information needed for its
What Are the Mendelian Laws of Inheritance?
Before the acceptance of Mendels research, the concept of blending was favored.
Klreuter and others believed that hereditary determinants existed in the egg and sperm cells,
which came together in a single cell
Meiosis is a specialized cell division used for sexual reproduction. The genetic information in the
chromosomes is shuffled, and the resultant cells, the gametes, typically receive one-half of the
full complement of chromosomes.
Shuffling of the
The Organizer and Organization of the Embryonic Axis (p. 930 932)
before gastrulation, transplanted blastular tissues will have their fate re-determined by their new
position. This is true of all parts of the blastula except the dorsal lip of the blastop
Three germ layers
Ectoderm outermost layer, gives rise to epidermis and nervous system.
Mesoderm middle layer, gives rise to muscles, bones, heart, blood, kidney and gonads.
Endoderm innermost layer, gives rise to visceral organs and lung.
Transcription has three stages
Initiation: Opening DNA and bringing in RNA polymerase
Elongation: adding nucleotides to lengthen the mRNA
Termination: releasing the completed mRNA
Genes may be located anywhere on a chromosome, and on either strand of a do
Three steps of translation
Initiation: mRNA, ribosome and tRNA are brought together.
Elongation: amino acids are added (via tRNA-mRNA interaction) to lengthen the peptide chain.
Termination: releasing the completed polypeptide and the mRNA from the ri
What Is the Evidence that the Gene Is DNA?
By the early twentieth century, geneticists had associated the presence of genes with
chromosomes and had begun researching which chemical component of chromosomes comprised this
Lecture #08 Photosynthesis
Photosynthesis is the conversion of light energy into chemical energy. It is important to
understand the mechanisms from light capturing to ATP, NADPH, and sugar production in a
Human body has ~3 x 1013 (30 trillion cells)
~10 billion mitosis per second; much division in bone marrow (RBC live 4 months) and epithelial lining
of gut (cells in harsh environment replaced every 2-3 days)
human feces is 20-30% dead epithelial cells (an
Hormone Release and Control Mechanisms
Simple on/off switch
e.g. ecdysone or juvenile hormone release in insects.
usually triggered by environmental or sensory cues, e.g. changes in light-dark cycle, inflation of
abdomen after a blood meal, presence of
Functional Organization of the Hypothalamic-Pituitary-Adrenal Axis in Response to Stress
the adrenal gland consists of an adrenal medulla, which releases epinephrine and norepinephrine
under neural control, and an adrenal cortex, which releases cortisol
Many eukaryotic chromosomes have repetitive sequences (which do not contain genes) called telomeres
at their ends that shorten after each round of cell division.
Eventually the telomeres shorten to the extent that they no longer stabilize the ends of the
Alleles are different forms of a gene
Alleles are different forms of a gene.
Each allele is given a symbol (e.g., S to represent smooth seeds and s to represent wrinkled).
True-breeding individuals have two copies of the same allele (i.e., they are homozy
During S phase, the centrosome replicates to form two centrosomes.
Each centrosome consists of a pair of centrioles, each a hollow tube lined with nine microtubules. The
centrioles are oriented perpendicular to each other.
Deciphering the Genetic Code
Artificial polynucleotides were synthesized and translated in a cell-free system.
The resulting polypeptides were sequenced.
For most Amino acids, there is more than one codon. The genetic code is redundant. But the genetic
Deoxoribose Nucleic Acid
Phosphate nucleotide, and base
Carbon 3 and carbon 5 are important.
DNA is a polymer of nucleotides.
The four nucleotides that make up DNA differ only in their nitrogenous bases.
There are two purines (adenine and guanine) and two
Development is the Progressive Restriction in Potential (pp. 408, 410 412)
the zygote is a totipotent cell; it has the potential to give rise to all cell types and an entire individual.
as development proceeds, cell become gradually multipotent, or plur
Febrile Response Resetting the Thermostat Upwards
Homeostatic systems change equilibrium set-points by feedforward control. [Feedback control
prevents change; feedforward control executes change.]
To increase body temperature, resetting is required. Aft
Experiments on bread mold established that genes determine enzymes
Because of lifes basis in the cell theory, scientists can assume that what is found in one organism
can apply to others, and they often search for a model organism.
The common bread mold N
Lecture #10 Inheritance, Genes and Chromosomes
Genetics is an enormous topic; we shall not be able to cover even a tenth of it superficially.
We will focus on Mendelian genetics. The work of Gregor Mendel is important; it forms th