Exam 2 Review for Final Flashcards
What is a karyotype and what is an ideogram?
Karyotype: the number and visual appearance of the chromosomes in the cell nuclei of an organism or species
Ideogram: schematic representation of chromosomes showing the relative size of the chromosomes and their banding patterns
(remember that mutations have to be larger than 4mb to be seen on a karyotype)
What are the parts of a chromosome (long arm, short arm, etc.)?
Chromosomes are made of DNA with nucleotide base pairs in a long sequence that have: p short-arm and q long arm that are tied together by a centromere
How may pairs of autosomes, and how many sex chromosomes do humans have?
Humans have 22 pairs of autosomes and 1 pair of sex chromosomes, making 23 pairs total
How does the medical and general usage of the word “gene” differ?
Genes used to be called only protein-coding sequences of DNA
Now, any functional unit of a chromosome is a “gene” (without medical circles)
What is a locus?
Locus is the exact physical location of a gene on a chromosome. It is the same in all people and marked by a p/q-# and usually given acronyms.
What are alleles?
Alleles are the term to describe the 2+ variations in a gene within a population.
Heterozygous vs. homozygous: homozygous states contain the same allele of the gene; homozygous states contain alternate alleles of a gene
What is the difference between genotype and phenotype?
Genotype: the particular combination of alleles that a person has for a certain locus.
Phenotype: the physical, observable reflection of a genotype; also, the presence or absence of certain traits
What is a SNP?
SNPs are single-nucleotide polymorphisms
DNA sequence variations occurring when a single nucleotide differs between members of a species or paired chromosomes in an individual. Almost all common SNPs only have two alleles. Genomic distribution of SNPs is not homogenous and occurs more frequently in non-coding regions.
What is imprinting? What is the difference between imprinting of the X chromosome, and imprinting of the autosomes?
Imprinting: a small number of genes are transcriptionally active only when transmitted by one of the two sexes/parents; homologous locus in the other parent is rendered “transcriptionally inactive”. Methylation and other epigenetic mechanisms may be employed.
Imprinting of the X Chromosome: in females, only one of the two X chromosomes will be active within a cell.
Imprinting of the Autosomes: see “imprinting” above.
There are 5 points of control for gene expression? The one most studied in terms of epigenetic influence is what stage?
CONTROL MECHANISMS: 5-Point Control (for boards)
Chromatin stage (most studied)
Transcriptional stage
Translational stage
Post-translational control into cytoplasm
Post-translational modification
Why does DNA naturally wrap around histones, and what epigenetic changes can occur to histone tails to encourage or discourage winding/unwinding?
DNA naturally wraps around histones due to Van Der Waals attractive forces of opposite charges
Histone Methylation: occurs at CpG islands; down-regulation of transcription
Histone Acetylation: neutralization of the histone charge, decreasing the attractive forces; up-regulation of unwinding and therefore transcription
Ubiquination, sumoylation, and phosphorylation may also occur
What is a promoter region on a gene, and why are promoter regions generally not methylated?
Promoter regions on a gene are typically CpG islands. If a promoter region is methylated, then the gene will be silenced, possibly causing cancer. (?)
What is the difference between exudates and transudates and which of those cause non-pitting edema?
Transudates: edema with low protein content and lower specific gravity and will produce pitting edema
Exudates: fluid with high protein content and cells and a higher specific gravity; non-pitting edema.
What is Virchow’s triad, and what are examples of the diseases/conditions contributing to stasis, vascular injury, and hypercoagulability?
Virchow’s Triad:
- Hypercoagulability: clotting disorders, oral contraceptives, malignancy, pregnancy, sepsis, thrombophilia, IBD
- Stasis: atrial fibrillation, immobility, venous obstruction, venous insufficiency/varicose veins
- Vascular Wall Injury: trauma/surgery, venepuncture, heart valve disease/replacement, atherosclerosis, catheters
What is the difference between an embolism and a thrombus?
Thrombosis: in coronary and cerebral arteries, heart chambers, aortic aneurysms, heart valves, DVTs resulting in vascular occlusion/infarction, embolism, thrombolysis, organization and recanalization
Embolism: any intravascular mass carried down bloodstream from site of origin, resulting in occlusion of a vessel