Flashcards in Lecture 1 Deck (72):
Molecular genetics def'n
Field of bio that studies the structure and function of genes at a molecular level
Albinism results from a defect in genes involved in which of following?
a. Hair color determination
b. Skin formation
c. Keratin productions
d. Melanin production
T/F: If a gene is recessive it may be inherited from one parent for the phenotype to be expressed.
False, defective gene must be inherited from each parent.
What may be the reason that there is a high freq of albinism in Hopi Native Americans?
This tribe believes albinos to be blessed, so they are treated with great admiration and respect.
Seen as "high" members in tribe hierarchy
When does a normal cell convert to a cancer cell?
When an oncogene mutates and becomes inappropriately activated.
Which of the following is most true about the relationship btw diseases and genes?
a. Defective genes always cause disease
b. Genes have no effect on cause or prevention of diseases
c. Genes affect our susceptibility to many diseases and disorders
d. Environmental circumstances has no effect on disease onset
What is advantage of using BabyGenes?
Screen for mutations not on most newborn screening panels
If find disorder, can intervene to improve quality of life for baby
Three aspects of regulation that genes must do correctly to be effective
Must regulate/control correct Mechanism
In correct Space/Area
At correct Time
A complete set of genetic instructions for any organism
T/F: Coding system for genomic information is very different among organisms
False, coding system for genomic info is VERY SIMILAR among organisms
Transmission Genetics/Classical genetics def'n
How traits are passed from one generation to the next
Gene structure, function and regulation
Study of the genetic composition of groups (populations) and how gene freq changes geographically over time - essentially study of evolution
Model genetic organisms
Organisms w/ characteristics that make them useful for genetic analysis
Six most extensively used model organisms in genetics:
6 Common characteristics of model organisms
Short generation time
Ability to carry out controlled genetic crosses
Ability to be reared in a lab environ.
Accumulated body of knowledge about organism's genetic system
Why are animal model organisms valuable?
Similarity among all living things
Drosphila (fruit flies) have been very useful in studying what?
Regulation of development, specifically Wnt genes, HOX genes, and Notch genes
What does the fact that HOX (homeobox) genes has remained unchanged over millions of yrs of evolution tell us?
HOX genes play a vital role in the general organization of the body in almost all organisms
What was first multicellular organism to have its whole genome sequenced?
Which model organism has served as one of the foundations for perfecting the genetic modification of food for cultivation and human consumption?
Which model organism is a primitive eukaryote but still has the basic genetic make-up that humans do?
Why are zebrafish a good model organism?
Fertilized egg to adult in ~13 days
Bodies are transparent up until day 12, so can modify a gene and see how organs are developing
What are some of the implications of all organisms having similar genetic systems?
a. That all life forms are genetically related
b. That research findings on one organism's gene function can often be applied to other organisms
c. That genes from one organism can often exist and thrive in another organism
d. All of the above
Miniature organism resides in sex cells (sperm) and miniature organism grows over time
All traits inherited from male parent (sperm)
Blending of inheritance
Genes blend/mix and are determined from a range bound by traits found in parents
According to blending of inheritance what should the height of a child born to one tall and one short parent be?
Height btw that of two parents
Problems with blending of inheritance theory
Don't always get intermediate when mix two extremes
When get intermediate, how do you then get the extremes back
Offspring can be taller than parents
Inheritance of acquired characteristics
Acquired traits become incorporated into hereditary info
Theory under umbrella of Inheritance of acquired characteristics
If an organism changes during its life in order to adapt to its environment, those changes are passed onto offspring
Lamarck's theory of giraffe evolution
Original short-necked ancestors stretched necks to grab food causing necks to grow incrementally and the resulting growth of neck was passed onto offspring.
As generations passed ever longer necks passed on
Genetic info travels from diff parts of the body to reproductive organs and packaged into sperm/egg and then passed on to resulting embryo
All cells contain complete set of genetic info
- Germ cells contain and transmit heritable info
- Somatic cells contain genetics info to carry out bodily functions but do not transmit hereditary info
All life composed of cells, and cells only arise from other cells
Traits are inherited in accord with defined principles
Study of genes, heredity, and genetic variation in living organisms
Main differences between Prok and Euk?
Prok - unicellular, Nucleus absent, smaller, circular DNA, small amount of DNA, eubacteria no histones/some archaea histones, no membrane bound organelles
Euk - unicellular or multicellular, Nucleus present, larger, chromosomes, histones, large amount of DNA, membrane bound organelles
Neither Prok or euk
Outer protein coat surrounding nucleic acid
Similarities between Prok and Euk cell reproduction
Reproduce perfect copy of parent's genome
High rate of replication
Carry two sets of genetic info organized as homologous pairs
23 pairs = 2n = 46 chromosomes total
Examples: Zygotes and somatic cells
Carry one set of genetic info
1n = 23 chromosomes
Similar but NOT identical
Each homologous chromosome carries same genes in same order, but the alleles for trait may not be the same
Staining of chromosomes
Each chromosome has DNA seq unique to that chromosome
Allow staining unique to each chromosome
Can be used in treatment of disease
Diploid cells have:
A. Two chromosomes
B. Two sets of chromosomes
C. One set of chromosomes
D. Two pairs of homologous chromosomes
Attachment point for spindle fibers/microtubules
Where kinetochores form
Unique DNA seq/proteins that form the stable tip/cap of a linear chromsome
Function of Telomeres
Linear chromosomes have exposed ends that can be easily damaged
Telomeres protect chromosomes from this damage
Origins of replication
Where DNA synthesis begins
Unique DNA seq/proteins that allow for replication of the chromosome to begin
Does circular DNA have telomeres?
Can the telomeres be easily replicated?
An extended period btw cell divisions: G1, S, and G2 phases
Phase check points
Key transition points
Mitotic phase - nuclear and cellular division
Mitosis and cytokinesis
Proteins necessary for cell division synthesized
Regulated decision point
After pass this cell is committed to dividing
When is the cell committed to dividing?
After G1/S checkpoint
DNA synthesis and replication
Cell prepares biochemically for mitosis
Only passed if DNA is completely replicated and undamaged after which cell can divide
Order of phases/checkpoints of cell cycle
G1, G1/S checkpt, S, G2, G2/M checkpt, Mitosis, Spindle-assembly checkpt, cytokinesis
Mitosis (in general)
Separation of sister chromatids
Separation of cytoplasm
Phases of mitosis
Chromosomes = Two sister chromatids
Mitotic spindle/centrosomes form
Nuclear membrane disintegrates
Spindle microtubules attach to chromatids
Chromosomes line up along metaphase plate
Sister chromatids separate and toward oppo poles
Chromosomes arrive at poles
Nuclear membrane reforms
Genetic consequences of cell cycle
Produces two cells that are genetically identical (but not always) w/ cell that gave rise to them
Have a full complement of chromosomes
Each daughter cells have half the cytoplasm and organelle content of parent cell
Why are the daughter cells resulting from mitosis NOT always identical to parent cell