exam 1 Flashcards
4 key elements of DNA
Cytosine (C), thymine (T), adenine (A), guanine (G
purines
adenine
guanine
pyrimidine
cytosine
thymine
when the cells are not dividing
G 0
cell that getting ready for division
amount of cytoplasm increase
G1
Formation of haploid cells from diploid cells
Meiosis
Is any inherited alteration of genetic material.
Mutation
Are agents, such as radiation and chemicals, that increase the frequency of mutations.
Mutagens
Involves the insertion or deletion of one or more base pairs to the DNA molecule.
Frameshift mutation
One base pair is substituted for another; may result in changes in amino acid sequence.
May or may not cause disease or problems
Base pair substitution or missense mutation
With Transcription:
RNA is synthesized from the ___ template via RNA
polymerase.
DNA
With Transcription:
DNA specifies a sequence of____
mRNA.
With Transcription:
Transcription continues until the _____ sequence is reached.
termination sequence is reached.
With Transcription:
mRNA then moves out of the nucleus and into the _____
cytoplasm.
With Transcription:
Gene ____ occurs.
Gene splicing occurs.
Is the process by which RNA directs the synthesis of a polypeptide via the interaction with transfer RNA (tRNA).
Translation
____ contains a sequence of nucleotides (anticodon) complementary to the triad of nucleotides on the mRNA strand (codon).
tRNA
_____ is the site of protein synthesis.
Ribosome
_____ helps mRNA and tRNA make polypeptides.
Ribosome
Contain 46 chromosomes (23 pairs)
One member from the mother; one from the father
Diploid cells
Somatic cells
Sperm and egg cells
Contain 23 chromosomes
Haploid cells
One member of each chromosome pair
Gametes
Are the first 22 of the 23 pairs of chromosomes in males and females.
The two members are virtually identical and are thus said to be homologous.
Autosomes
Make up the remaining pair of chromosomes.
In females, it is a homologous pair (XX).
In males, it is a non-homologous pair (XY).
Sex chromosomes
The length and centromere location determine the ordered display of chromosomes
Karyotype
Have a multiple of the normal number of chromosomes.
Haploid and diploid cells are forms.
Euploid cells
: Is a zygote that has three copies of each chromosome.
Triploidy
An euploid cell has more than the diploid number.
Polyploid cells:
Triploidy, Tetraploidy
Has four copies of each chromosome (92 total).
Tetraploidy:
_____ fetuses do not surviveor are stillborn or spontaneously aborted.
Triploid and tetraploid
Usually presents less serious consequences than autosomes.
Y chromosome usually causes no problems since it contains little genetic material.
For the X chromosome, inactivation of extra chromosomes largely diminishes their effect.
Aneuploidy of sex chromosomes
Chromosomes 13, 18, and 21 can survive;
most others do not.
Trisomy
Only an extra portion of a chromosome is present in each cell.
Is not as severe as trisomy.
Partial trisomy
Are trisomies that occur in only some cells of the body.
Body has two or more different cell lines, each of which has a different karyotype.
Chromosomal mosaics
Trisomy
Partial trisomy
Chromosomal mosaics
Autosomal Aneuploidy
Most common cause is maternal nondisjunction
Down syndrome
Autosomal Aneuploidy
Is the best-known example of aneuploidy.
Trisomy 21
Occurs 1 in 800 live births.
Manifestations: Mental challenges; low nasal bridge; epicanthal folds; protruding tongue; flat, low-set ears; and poor muscle tone.
Risk increases with maternal age.
Has an increased risk of congenital heart disease, respiratory infections, and leukemia.
Down syndrome
Occurs 1 in 400 males and 1 in 650 females.
Trisomy X is one of the most common aneuploidy.
Females have three X chromosomes.
Occurs 1 in 1000 female births.
Symptoms are variable and include sterility, menstrual irregularity, and/or cognitive deficits.
Symptoms worsen with each additional X chromosome.
Sex Chromosome Aneuploidy
Females have only one X chromosome
Denoted as karyotype 45,X.
Absence of ovaries (sterile)
Short stature
Webbing of the neck
Widely spaced nipples
High number of aborted fetuses
X chromosome that is usually inherited from the mother
Occurs 1 in 2500 female births.
Teenagers receive estrogen.
Turner syndrome
Sex Chromosome Aneuploidy
Individuals with at least one Y and two X chromosomes.
Characteristics include: Male appearance Femalelike breasts (gynecomastia) Small testes Sparse body hair 1 in 1000 male births
Some individuals can be XXXY and XXXXY; will have male appearance; abnormalities will increase with each X; can also have an extra Y chromosome.
Disorder increases with the mother’s age.
Klinefelter syndrome
Sex Chromosome Aneuploidy
Abnormalities of Chromosomal Structure:
Chromosome breakage or loss of DNA
Example: Cri du chat syndrome or “cry of the cat”
Low birth weight, mentally challenged, and microcephaly
Deletions
Abnormalities of Chromosomal Structure:
Excess genetic material
Usually have less serious consequences
Duplications
Abnormalities of Chromosomal Structure:
Chromosomal rearrangement in which a chromosome segment is inverted: ABCDEFG becomes ABEDCFG
Usually affects offspring
Inversion
Element of Formal Genetics where:
Is the location occupied by a gene on a chromosome.
Locus:
Is one of several different forms of a gene at a locus.
Allele
Is a locus that has two or more alleles that occur with appreciable frequency.
Polymorphism or polymorphic
When genes are identical
Homozygous:
When genes are different
Heterozygous:
Is the composition of genes at a given locus.
Genotype
Is the outward appearance of an individual.
Results from genotype and the environment.
Phenotype
Four major types of genetic diseases
Autosomal dominant
Autosomal recessive
X-linked dominant
X-linked recessive
The union of a normal parent with an affected heterozygous parent usually produces the affected offspring.
half will be heterozygous and will express the disease and half will be normal.
Autosomal Dominant Inheritance
example: Huntington’s disease
Abnormal allele is recessive, and the person must be homozygous to express the disease.
Trait usually appears in the children, not in the parents.
Autosomal Recessive Inheritance
example: cystic fibrosis
Is the mating of two related individuals.
Offspring are termed inbred.
Proportion of shared genes depends on the closeness of the biologic relationship.
Consanguinity
Is a disorder that involves X and Y chromosomes.
Y-linked disorders are uncommon because the Y chromosome contains relatively few genes.
Males are affected more often with X recessive conditions.
X-Linked Inheritance
Is a process by which one X chromosome in the somatic cells of females is permanently inactivated.
X inactivation
Begins during the sixth week of gestation.
One copy of the Y chromosome is sufficient to initiate the process of gonadal differentiation that produces a male fetus.
Number of X chromosomes does not alter this process.
Sex determination
The process by which cells program themselves to die is called:
apoptosis.
A cell can ingest bacteria or cellular debris through the process of:
phagocytosis
Activity of the Cell Cycle where:
Cells that are not actively dividing
Most normal cells in this stage most of the time
G0
Activity of the Cell Cycle where:
Cell is getting ready for division by taking on extra nutrients, making more energy, & growing extra membrane. The amt. of cell cytoplasm also increases
normal cell functions occur
G1
Activity of the Cell Cycle where:
DNA replication and synthesis
2 copies of each chromosome
S
Activity of the Cell Cycle where:
Production of proteins important to cell division and in normal physiological function after mitosis is complete
G2
Activity of the Cell Cycle where:
the DNA in the nucleus pulls apart and creates 2 nuclei, followed by the cell separating into 2 cells each with on nucleus
M (mitosis)
the part of the cell cycle where
(growth phase) nuclear division
mitosis
cytoplasmic division
cytokinesis
what are the 3 phases of interphase?
G1
S
G2
what are the phases of mitosis
prophase
metaphase
anaphase
telophase
Are chemical modifications of deoxyribonucleic acid (DNA) sequences that alter the expression of genes, resulting in disease and phenotypic variations (upon genetics).
Epigenetics
4 Types of epigenetic modifications
DNA methylation
Histone modification
Microribonucleic acids (miRNAs) or mature miRNAs [miRs])
Specific environmental or nongenetic factors
(such as diet and exposure to certain chemicals, can affect epigenetics.)
4 Types of Cancer -genomic mechanism
Hereditary
Chromosomal
Epigenetic Biochem. Modification
Sporadic mutation
Specific genetic changes passed from parent to child
Hereditary
Genomic Mechanism where:
Hallmarks:
Early age of onset
Development of multiple types of cancer in a single person
Bilateral tumors in paired organs
Cancer in gender less affected i.e. breast cancer in males
Same or similar cancer in many biological relatives
Hereditary
Genomic Mechanism where:
5-10% of cancer cases
Inheritance predisposition occurs on a single gene mutation
Susceptibility begins a genetic alteration in parental gamete (sperm/ova) and incorporated into zygote
Every somatic cell in body will carry this germline mutation
Hereditary
4 types of genetic alteration disrupt cell differentiation and function
DNA repair
Oncogenes
Chromosomal translocations
Tumor suppressor genes
3 basic chromosomal alteration that effect Cancer
Alteration in copy # of chromosomes inside the nucleus of the cell
Translocation of one or more segments on one or more chromosomes to a new position on the same of different chromosome
Structural instability of chromosomes leads to further impairments in the cells ability to repair DNA or recover form the slippery slope of tumorigenesis
4 types of Epigenetic Biochemical Modification
DNA methylation
Genomic imprinting
Histone modification
miRNA
Cellular information that is inherited during cell division but is not encoded in the DNA sequence of the genome.
Epigenetic Biochemical Modification
are both inherited and acquired in response to environmental exposure early in life
Epigenetic Biochemical Modification
Increases activity of oncogenes.
increases as tumors progress from benign neoplasms to malignancy.
Hypomethylation (decreased methylation).
Ability to inhibit tumor formation: Decreases
Promoter region of the RB1: Can cause retinoblastoma
BRCA1: can lead to inherited breast cancer
VHL promoter region: associated with von Hippel-Lindau disease, in which renal cell carcinomas frequently occur
Hypermethylation in promoter regions of tumor-suppressor genes.
When MLH1 becomes inactive, damaged DNA accumulates, eventually resulting in colon tumors.
Is the major cause of one form of inherited colon cancer—hereditary nonpolyposis colorectal cancer.
Methylation of the promoter region of a gene: MLH1
Results
Histone acetylation and deacetylation
Alterations in chromatin
Histone Modification
Cancer that happen de novo “by chance”
Comprises 90-95% of all cancers not attributed to gene mutations or chromosomal aberrations
Sporadic mutations
Is the process of gene silencing, in which genes are predictably silenced, depending on which parent transmits them
Genomic Imprinting
Is the deletion of approximately 4 million base (Mb) pairs of the long arm of chromosome 15.
Is inherited from the father.
Prader-Willi Syndrome
Has the same deletion of approximately 4 Mb pairs of the long arm of chromosome 15.
Is inherited from the mother.
Clinical manifestations:
Severe mental retardation
Seizures
Ataxic gait
Angelman Syndrome
broad term for a class of diseases characterized by abnormal cells that grow and invadehealthy cells in the body.
Cancer
slow growth well defined capsule no invasive well differentiated low mitotic index does not metastasize
benign
rapid growth not encapsulated invasive poorly differentiated high mitotic index can spread distantly (metastasize
malignant
Malignant epithelial tumors:
Carcinomas
Malignant tumor of Ducts or glands
Adenocarcinoma
Malignant connective tissue tumors
Sarcomas
Cancers of lymphatic tissue
Lymphomas
Cancers of blood-forming cells
Leukemias
Are preinvasive epithelial malignant tumors of glandular or squamous origin.
not malignant
Carcinoma in situ (CIS)
Are substances produced by benign or malignant cells.
Are found on or in a tumor cell, in the blood, in the spinal fluid, or in urine.
Tumor Markers
Is the process during which a normal cell becomes a cancer cell.
Transformation
Are normal nonmutant genes that code for cellular growth.
Proto-oncogenes
Are mutant genes that, in their nonmutant state, direct protein synthesis and cellular growth.
Oncogenes
Encode proteins that, in their normal state, negatively regulate proliferation.
Tumor-suppressor genes
Are also referred to as anti-oncogenes.
is a G protein that relays a growth signal from a growth factor receptor on the plasma membrane to a cascade of protein kinases
Ras protein
Positive signal for cell proliferation
master regulator
MYC protein:
Changes occur in one or a few nucleotide base pairs.\
Ras gene converts a regulated proto-oncogene to an unregulated oncogene, accelerating growth.
Point mutations
Piece on one chromosome is transferred to another.
Chromosome translocation
A small piece of chromosome is duplicated over and over.
Results in an increased expression of an oncogene.
Gene amplification
Are responsible for the maintenance of genomic integrity.
Encode proteins that are involved in repairing damaged DNA, such as the damage that occurs with errors in DNA replication, mutations caused by ultraviolet or ionizing radiation, and mutations caused by chemicals and drugs.
Caretaker genes
first factor in cancer metastasizing
Cancer cells secrete enzyme and motility factors
Are protective caps on each chromosome that are held in place by a telomerase.
Telomeres
become smaller and smaller with each cell division.
Telomeres
Viruses have been associated with human cancer
Epstein-Barr virus (EBV) Kaposi sarcoma herpesvirus (KSHV) Human T-cell lymphotropic virus type 1 Human papillomavirus (HPV) Chronic hepatitis B &C infections
Active ______ predisposes a person to cancer.
inflammation
This bacteria can both directly and indirectly produce genetic and epigenetic changes in infected stomachs.
bacterial cause of cancer
Helicobacter pylori
Is the spread of cancer cells from the site of the original tumor to distant tissues and organs through the body
Metastasis
Local spread
Is a prerequisite for metastasis and the first step in the metastatic process.
Invasion
stage of cancer where
Is confined to its organ of origin
stage 1
stage of cancer where
Is locally invasive.
stage 2
stage of cancer where
Has advanced to regional structures
stage 3
stage of cancer where
Has spread to distant sites.
stage 4
Symptom complexes are triggered by a cancer but are not caused by direct local effects of the tumor mass.
Are caused by biologic substances released from the tumor (e.g., hormones) or by an immune response triggered by the tumor.
Paraneoplastic syndromes
Is the most frequently reported symptom of cancer and cancer treatment.
Fatigue
Is the most severe form of malnutrition.
Leads to protein-calorie malnutrition and progressive wasting.
Cachexia
Is a decrease of hemoglobin in the blood.
anemia
Eradicates enough tumor cells to enable the body’s natural defenses to eradicate the remaining cells.
Chemotherapy
Causes shrinkage or the disappearance of tumors.
Induction chemotherapy:
Is administered after the surgical excision with a goal of eliminating micrometastases.
Adjuvant chemotherapy:
Is administered before localized (surgical or radiation) treatment.
Neoadjuvant chemotherapy:
Is used to kill cancer cells while minimizing the damage to normal structures.
Radiation Therapy
Damages cells by imparting enough ionizing radiation to cause molecular damage to the DNA.
Causes irreversible damage to normal cells.
Ionizing radiation
Radiation Seeds are implanted.
Brachytherapy
Is a definitive treatment of cancers that do not spread beyond the limits of surgical excision
Surgery
Inhibit the binding of proteins that promote transcription; the gene becomes transcriptionally inactive.
Histone Modification
The Warburg Effect
increase in the rate of glucose uptake and preferential production of lactate, even in the presence of oxygen.
formation of new blood vessels
angiogenesis
tumors more the 1mm requires _____
own blood supply
contain genes.
Chromosome
The sequence of three bases _____ direct the production of amino acids.
(codons)
Termination and nonsense codons stop the production of _____
protein.
having an abnormal number of chromosomes in a haploid set.
Aneuploidy
the first appearance of chromosomes. As the phase proceeds, each chromosome is seen as two identical halves called chromatids
prophase
the spindle fibers begin to pull the centromeres of the chromosomes
metaphase
When the sister chromatids are separated, each is considered to be a chromosome. Thus the cell has 92 chromosomes during this stage.
anaphase
a new nuclear membrane is formed around each group of 46 chromosomes, the spindle fibers disappear, and the chromosomes begin to uncoil
telophase
a form of modified cellular metabolism found in cancer cells, which tend to favor aerobic glycolysis even in the presence of oxygen
Warburg effect
5 steps of cancer metastases
cancer cells secrete enzyme and motility factors
cancer cells escape into circulation
new tissue invaded downstream
malignant cells target specific sites
metastatic tumor appears
the loss of cellular differentiation
anaplasia
an increase in the number of cells in an organ or tissue resulting from an increased rate of cellular division.
hyperplasia
the reversible replacement of one mature cell type (epithelial or mesenchymal) by another, sometimes less differentiated, cell type.
Metaplasia
abnormal changes in the size, shape, and organization of mature cells.
dysplasia
loss of TP 53 results in
increase of malignancy
Bodily tissues are thought to release this protein to signal the need for additional oxygen
VEGF
