Anchorage dependence
...External factor of cell cycle control system in with most animal cells must be attached to a subratum in order to divide.
Autosomes
...Any chromosome not considered as a sex chromosome, or is not involved in sex determination. It occurs in pairs in somatic cells and singly in sex cells (gametes).
Benign tumor
...Abnormal cells remain at the original site and are usually surrounded by a capsule.
Cdk
...A family of kinases that, once activated by cyclin, regulate the cell cycle by adding phosphate groups to a variety of protein substrates that control processes in the cycle.
cyclin-dependent-kinase
Centromere
..1) The constricted region joining the two sister chromatids that make up an X-shaped chromosome.
(2) The site where kinetochore is formed.
.
Centrosome
...cell biology) The organelle located near the nucleus in the cytoplasm that divides and migrates to opposite poles of the cell during mitosis, and is involved in the formation of mitotic spindle, assembly of microtubules, and regulation of cell cycle pr
Checkpoint
...Cell cycle checkpoints are control mechanisms that ensure the fidelity of cell division in eukaryotic cells. These checkpoints verify whether the processes at each phase of the cell cycle have been accurately completed before progression into the next
Chromatin
...Mass of genetic material composed of DNA and proteins that condense to form chromosomes during eukaryotic cell division. Chromatin is located in the nucleus of a cell.
During prophase of mitosis, chromatin fibers become coiled into chromosomes with eac
Chromosome
...A chromosome is a long, stringy aggregate of genes that carries heredity information (DNA) and is formed from condensed chromatin. The centromere region of a chromosome joins two identical copies of the chromosome known as sister chromatids. Chromosome
Cleavage
.(1) A division or separation of form.
(2) (cell biology) The act or state of splitting or dividing of a cell, particularly during the telophase of (animal) cell division.
(3) (embryology) The repeated division of a fertilized ovum, producing a cluster of
Cyclin
...one of a family of closely related protiens that regulate the cell cycle in eukaryotic cells
A class of proteins that fluctuate in concentration at specific points during the cell cycle and that regulate the cycle by binding to a kinase.
Cytokinesis
...The division of the cytoplasm and the plasma membrane following the division of the nucleus resulting into two cells, each having its own nucleus and cytoplasm surrounded by a plasma membrane.
Density -dependent
...(Science: radiology) The amount of darkness or light in an area of a scan reflects the compactness and density of tissue. Differences in tissue density are the basis for CT and MR scans.
2. (Science: microscopy) logarithm to the base 10 of the reciproc
inhibition
...(Science: chemistry, pharmacology) a molecule which represses or prevents another molecule from engaging in a reaction. Arrest or restraint of a process.
Diploid
...A cell or an organism consisting of two sets of chromosomes: usually, one set from the mother and another set from the father. In a diploid state the haploid number is doubled, thus, this condition is also known as 2n.
Gametes
...A reproductive cell or sex cell that contains the haploid set of chromosomes, e.g. spermatozoon or sperm cell (male reproductive cell) and egg cell or ovum (female reproductive cell).
(2) A mature haploid reproductive cell as produced by gametogenesis,
Haploid
...1) The number of chromosomes in a gamete of an organism, symbolized by n.
(2) A cell or an organism having half of the number of chromosomes in soma
Homologous chromosomes
...A pair of chromosomes having the same gene sequences, each derived from one parent.
Kinetochore
...A specialized condensed region of each chromosome that appears during mitosis where the chromatids are held together to form an X shape; the centromere is difficult to sequence.
Malignant tumor
...Abnormal cells invade surrounding tissues (invasive tumor) and can metastasize
Mitosis
...The process where a single cell divides resulting in generally two identical cells, each containing the same number of chromosomes and genetic content as that of the original cell.
Recombinant chromosome
...A chromosome in an offspring that has a genotype not found in either parent, due to crossing over in meiosis
Sister Chromatids
...Two identical strands joined by a common centromere as a result of a chromosome that duplicated during the S phase of the cell cycle.
Somatic cells
...The word "somatic" is derived from the Greek word soma, meaning "body". Hence, all body cells of an organism - apart from the sperm and egg cells, the cells from which they arise (gametocytes) and undifferentiated stem cells - are somatic cells.
Zygote
...A cell in diploid state following fertilization or union of haploid male sex cell (e.g. sperm) and haploid female sex cell (e.g. ovum).
1. Describe how chromosome number changes throughout the human life cycle.
egg is haploid so it has n genomic content. Then when sperm enters it becomes a zygote with 2n genomic content. Stays that way (In autosomes at least) forever.
2. List the phases of the cell cycle and describe the sequence of events that occurs during each phase.
Interphase: G1 phase: growth of cell, organelles made
G0 phase: non-dividing stage
S phase: if cell has committed to dividing, DNA is copied
G2 phase: more growth, preparation for dividing
Mitotic phase: Prophase: Chromosomes become visible as they conden
3. List the phases of mitosis and describe the events characteristic of each phase. Be able to draw and/or recognize each of the phases.
THE "MITOTIC" CELL CYCLE
The mitotic phase alternates with interphase in the cell cycle: an overview
5. List the phases of the cell cycle and describe the sequence of events that occurs
during each phase.
a. Interphase = 90% of the cell cycle
b. Growth in
4. Compare cytokinesis in animals and plants.
Animal cells lack a cell wall so cytokinesis is accomplished by pinching the
plasma membrane in half. At the midpoint of the cell, a cleavage furrow begins
as a ring of microfilaments contracts and pinches the cell in two. Plant cells have
the hard cell w
5. Describe the roles of checkpoints in the cell cycle control system, when do they occur? What are the checking for?
Checkpoints are times during the cell cycle when the cell confirms that certain
events have happened or materials made before moving into the next phase. At
the G1 or restriction check point, the cell decides to move ahead and commit to
dividing or stay i
6. Compare proto-oncogenes and tumor suppressor genes. How does each contribute to a cell becoming cancerous?
proto-oncogenes (e.g., ras) and tumor-suppressor genes (e.g., APC) � play a key role in cancer induction. These genes encode many kinds of proteins that help control cell growth and proliferation; mutations in these genes can contribute to the development
7. Explain why fertilization and meiosis must alternate in all sexual life cycles.
Meiosis maintains the normal diploid number by halving the number to make the gametes and then allowing the diploid number to be restored through fertilization
8. List the phases of meiosis I and meiosis II and describe the events characteristic of each phase. Be able to draw and/or recognize each of the phases.
* Interphase: Before meiosis begins, genetic material is duplicated.
* First division of meiosis
o Prophase 1: Duplicated chromatin condenses. Each chromosome consists of two, closely associated sister chromatids. Crossing-over can occur during the latter
9. Describe the process of synapsis during prophase I and explain how genetic recombination occurs.
Prophase1: tetrads form by the synapsis of homologous chromosome. this is when crossing over occurs which is the exchange of genetic material across the synapse between either homologous chromosome.
10. Distinguish between mitosis, meiosis I and meiosis II.
Mitosis
1 Mitosis takes places in somatic cells.
2 It involves only one division.
3 It results in production of two daughter cells.
4 Both the daughter cells show genetic Similarly with the parent cell. The chromosome number remains constant.
5 Prophase i
11. Explain how independent assortment of chromosomes, crossing over, and random fertilization contribute to genetic variation in sexually reproducing organisms.
Crossing over occurs during prophase I of meiosis I. It involves the switching of genes between the non-sister chromatids of homologues which allows the novel mixture of maternal and paternal genetic material with new, recombinant
chromosomes. Another lay
Compare normal cells with cancerous cells in terms of cell division.
Normal cells exhibit density dependent inhibition so that when conditions
become too crowded, the cells stop dividing. Cancer cells lack this density
dependent inhibition. Normal cells also show anchorage dependence, typically
preferring to be attached to
Distinguish between benign, malignant and metastatic tumors.
Any tumor is a mass of abnormal cells that are not exhibiting the normal cell
control. A benign tumor is one that stays in the original area and typically is not
damaging unless it becomes very large and affects other organs' function.
Benign tumors can o
.Describe three events that occur during meiosis I but not during mitosis.
1.Synapsis and crossing over in prophase I: Homologous chromosomes physically connect and exchange genetic information
2.At the metaphase plate, there are paired homologous chromosomes (tetrads), instead of individual replicated chromosomes
3.At anaphase
Describe the roles of checkpoints, cyclin, Cdk, and MPF in the cell cycle control system
Cyclin is a regulatory protein that a kinase much be attached to. Cyclin gets its name from its cyclically fluctuating concentraion in the cell. Because of this requirement, these kinases are called cyclin-dependent kinases, CDK's. The CDK rises and falls
Anticodon
A sequence of three adjacent nucleotides located on one end of transfer RNA. It bounds to the complementary coding triplet of nucleotides in messenger RNA during translation phase of protein synthesis.
Antiparallel
especially of vectors) parallel but oppositely directed; "antiparallel vectors".
Chromatin
The material of which the chromosomes of organisms other than bacteria (i.e., eukaryotes) are composed.
Codon
A sequence of three nucleotides which together form a unit of genetic code in a DNA or RNA molecule.
Deletion
A type of gene mutation wherein the deletion (as well as addition) of (a number of) nucleotide(s) causes a shift in the reading frame of the codons in the mRNA, thus, may eventually lead to the alteration in the amino acid sequence at protein translation.
Exons
A segment of a DNA or RNA molecule containing information coding for a protein or peptide sequence
Frameshift mutation
A type of gene mutation wherein the addition or deletion of (a number of) nucleotide(s) causes a shift in the reading frame of the codons in the mRNA, thus, may eventually lead to the alteration in the amino acid sequence at protein translation
Histone
Histone acetyltransferases (HAT) are enzymes that acetylate conserved lysine amino acids on histone proteins by transferring an acetyl group from acetyl CoA to form ?-N-acetyl lysine.
Insertion
Science: genetics) a rare nonreciprocal translocation involving three breaks in which a segment is removed from one chromosome and then inserted into a broken region of a nonhomologous chromosome.
Introns
Non-coding, intervening sequences of dna that are transcribed, but are removed from within the primary gene transcript and rapidly degraded during maturation of messenger rna. most genes in the nuclei of eukaryotes contain introns, as do mitochondrial and
Messenger RNA
The form of RNA in which genetic information transcribed from DNA as a sequence of bases is transferred to a ribosome
Missense mutation
A form of point mutation resulting in a codon that codes for a different amino acid, and thus, causes the synthesis of a protein with an altered amino acid sequence during translation.
Mutagen
An agent, such as radiation or a chemical substance, that causes genetic mutation.
Point mutation
A mutation affecting only one or very few nucleotides in a gene sequence
Promoter
A site in a DNA molecule at which RNA polymerase and transcription factors bind to initiate transcription of mRNA
Reading frame
A reading frame in a sequence of nucleotides in dNA that contains no termination codons and so can potentially translate as a polypeptide chain.
Replication fork
A Y-shaped region in a chromosome that serves as the growing site for dna replication.
Ribosomal RNA
A nucleic acid found in all living cells. Plays a role in transferring information from dNA to the protein-forming system of the cell.
More specifically, rRNA sits in the Ribosome, decoding the mRNA into various amino acids and assisting in translation
RNA polymerase
Rna polymerase (RNAP or RNApol) is an enzyme that is responsible for making rna from a dna template. In all cells RNAP is needed for constructing rna chains from a dna template, a process termed transcription. In scientific terms, RNAP is a nucleotidyl tr
RNA splicing
A two step reaction in which introns are removed from a primary rna transcript and exons are joined together to form a mature mrna. An intron usually contains a clear signal for splicing, but in some cases a splicing signal may be masked by a regulatory p
Semiconservative replication
The normal process of DNA synthesis, in which the two original strands of the molecule separate, and each acts as a template on which a new complementary strand is laid down.
Read more: http://www.answers.com/topic/semiconservative-replication#ixzz1tN9zUP
Silent mutation
A form of point mutation resulting in a codon that codes for the same or a different amino acid but without any functional change in the protein product.
Telomerase
The enzyme that is concerned with the formation, maintenance, and renovation of telomeres, the ends of chromosomes
Telomers
Either (free) end of a eukaryotic chromosome; telomeres act as caps to keep the sticky ends of chromosomes from randomly clumping together.
Template strand
Transcription is the process of creating an equivalent RNA copy of a sequence of DNA . Both RNA and DNA are nucleic acids, which use base pairs of nucleotides as a complementary language that can be converted back and forth from DNA to RNA in the presence
Termiantor
3.A sequence of polynucleotides that causes transcription to end and the newly synthesized nucleic acid to be released from the template molecule
Transcription unit
A stretch of DNA being transcribed into an RNA molecule.
Transfer RNA
Known as trna. Short-chain rna molecules present in the cell (in at least 20 varieties, each variety capable of combining with a specific amino acid) that attach the correct amino acid to the protein chain that is being synthesized at the ribosome of the
Transformation
The change undergone by an animal cell upon infection by a cancer-causing virus.
b. The alteration of a bacterial cell caused by the transfer of DNA from another bacterial cell, especially a pathogen.
1. Explain how the experiments performed by the following scientists provided evidence that DNA is the genetic material
a. Frederick Griffith
. Transformed Pneumococcus
ii. Experimental: heat-killed smooth + live rough killed
iii. Controls
.Live smooth killed
.Live rough didn't
.Heat-killed smooth didn't
.Heat-killed rough didn't
iv. Conclusion: a substance transferred the smooth trait
b. Oswald Avery, Maclyn McCarty, and Colin MacLeod
...i. Purified components of the smooth bacteria
ii. Only DNA could transform
c. Alfred Hershey and Martha Chase
i. System: T2 bacteriophage of E. coli
ii. Differential labeling
.T2 grown in radioactive sulfur had labeled protein
.T2 grown in radioactive phosphorus had labeled DNA
iii. Experiment
.Infect
.A short time later knock phage off with a blender
.Centrifuge
d. Erwin Chargaff
. Analyzed DNA from a variety of organisms
ii. Results
.Amounts of ATGC varied
.But A=T and G=C
iii. Conclusion: DNA not so simple, specifically varies by species
e. James Watson, Francis Crick and Rosalind Franklin
evidence they used. Explain the significance of the research of Rosalind Franklin.
a. Known covalent structure
.Sugar-phosphate backbone
.One nitrogen base attached to each sugar
b. From Rosalind Franklin's X-ray crystallography
.Helix
.Constant width of
2. Describe the structure of DNA. How does this structure account for Chargaff's rules?
...Chargaff found that a peculiar regularity in the ratios of nucleotide bases. In the DNA of each species he studies, the number of adenines approximately equaled the number of thymine, and the number of guanines approximately equaled the number of cytos
origins of replication
... unique dNA sequence of a replicon at which dNA replication is initiated and proceeds bidirectionally or unidirectionally. It contains the sites where the first separation of the complementary strands occurs, a primer rNA is synthesised, and the switch
replication forks
...Replication fork) The replication fork is a structure that forms within the nucleus during DNA replication. It is created by helicases, which break the hydrogen bonds holding the two DNA strands together
DNA polymerase
...An enzyme that can synthesize new DNA strands using a DNA template; several such enzymes exist
Okazaki fragments
...Relatively short fragment of DNA synthesized on the lagging strand during DNA replication.
DNA ligase,
... enzyme involved in dna replication. The dna ligase of E. Coli seals nicks in one strand of double stranded dna, a reaction required for linking precursor fragments during discontinuous synthesis on the lagging strand. Nicks are breaks in the phosphodi
primer
...short pre-existing polynucleotide chain towhich new deoxyribonucleotides can be added by dNA polymerase
primase,
...The enzyme that polymerises nucleotide triphosphates to form oligoribonucleotides in a 5' to 3' direction. The enzyme synthesises the rNA for RNA dNA sequences that later become okazaki fragments and also rNA primers for some types of phage using an sD
helicase
...a prokaryote enzyme that uses the hydrolysis of atp to unwind the dna helix at the replication fork, to allow the resulting single strands to be copied.
two molecules of atp are required for each unwinding of the duplex.The enzyme that is capable of un
topoisomerase
...An enzyme which introduces or removes overwinding or underwinding of the DNA circular duplex by causing a nick, rotating the strands, and then ligating them
single strand binding proteins
...SSB's are proteins responsiblefor holding the replication fork of DNAopen while polymerases readthe templates.
antiparallel,
...A term used to describe the opposite orientations of the two strands of a DNA double helix; the 5' end of one strand aligns with the 3' end of the other strand
leading strand
...The dna strand that is synthesised continuously during replication
lagging strand
...The dna strand that is replicated discontinuously from the 5' to the 3' direction.
4. Describe the structure and function of telomers and their significance in germ cells and cancerous cells
...
Immortal cancer cells escape telomere loss by switching on a gene that expresses an enzyme called telomerase. This unusual enzyme is a reverse transcriptase that has an RNA template and a catalytic portion. At each round of DNA replication, telomerase
5. Explain how information flows from gene to protein. Distinguish between transcription and translation
...a. Transcription = DNA bases RNA bases by complementarity
b. Translation = RNA bases amino acid sequence
6. Explain the general process of transcription, including the three major steps of initiation, elongation, and termination. How is RNA modified after transcription in eukaryotic cells?
...a. Initiation
i. Small subunit binds to mRNA leader or 5' cap and tRNAmet in P-site
ii. Large subunit then binds
iii. Protein initiation factors and energy from GTP are required
b. Elongation
i. Next tRNA binds codon under A-site; uses elongation facto
7. Describe the process of translation (including initiation, elongation, and termination) and explain which enzymes, protein factors and energy sources are needed for each stage.
...Initiation brings together the mRNA transcript, the first tRNA carrying the first amino acid of the polypeptide and the 2 subunits of the ribosomes. This establishes the reading frame from this point on. Elongation continues as new amino acids are adde