Genetics Test 1 Flashcards
Be able to describe a virus.
Neither prokaryotic nor eukaryotic. There is even debate on whether they are living or not. Cant replicate alone, it needs to infect a cell.
Prokryotes
Unicellular
No nucleus
Not membrane bound
Not s much in them
DNA isnt tightly packed
Single circular chromosome
Eukaryotes
Yes nucleus
Can be unicellular or multicellular
Multiple linear chromosomes within nucleus (tightly packed around histones)
Understand the implications of the fact that all organisms use similar genetic systems.
All living things use similar genetic systems and are constructed from cells
When is something a good genetic model
Small, short lived, lots of offspring, genetic similarity, can be mutated
Give some examples of how genetics is important in today’s society.
Help affect traits and health
Important in agruculture (selective breeding and GMOs
Medicine
Development, evolution, etc.
Nucleic acids
encode the information required for the creation and maintenance of biological creatures.Nucleic acids are polymers of nucleotides.
Know the four nitrogenous bases in DNA and which ones are purines vs. pyrimidines (2 vs. 1 ring) and how this determines constant width of the DNA helix
Purines (2) - adenine and guanine
Pyrimidines (1)- thymine and cytosine
Pairs: adenine and thymine; guanine and cytosine
antiparallel
antiparallel - they are the same but go in opposite directions
DNA replication requirements
- Template must be single stranded
- Raw materials (dNTPs)
- Enzymes need to read template and assemble raw materials
Be able to describe all the various steps of DNA synthesis (general)
Initiation, unwinding, elongation, termination
initiation
Initiator proteins bind to origin and separate stands of a small section of DNA
Unwinding
- DNA Helicase-
* Unwinds DNA
*ssDNA binding protein -
*Keeps the strands separated
*DNA gyrase -
Relieives supercoiling
List and explain at least 3 differences between prokaryotic and eukaryotic DNA replication.
Single origin in prokaryotic and several in eukaryotic
The gyrase relieves supercoilding of helicase in prokayriotics and the topoisomerase does it in Eukaryotic
Replication is continuous in prokaryotic and based on cell cycle in eukaryotic
Binary fission
starts on specific place on circular chromosome (origin of replication). The origins move away from each other and SMC encircle DNA and help chromosomes from getting tangled in replication. Then cell walls form.
Cell reproduction in eukaryotes compared to prokaryotes
Similar to prokaryotes but way more complex.
Mitosis
single nuclear division. Newly formed cell is identical
Meiosis
two divisions, newly formed cell is half
Aneuploidy
An increase or decrease in # of individual chromosome
types of anueploidy
nullisomy, monosomy, trisomy, tetrasomy
Nullisomy
loss of both homologous pairs of chromosomes
Monosomy
loss of a single chromosome
Trisomy
gain of a single chromosome
Tetrasomy
gain of two homologous chromosomes
types of polyploidy
autopoloploidy and allopoloploidy
polyploidy
presence of more.than 2.setsofchromosomes (common in plants)
translocations on phenotype
Nonreciprocal
Reciprocal
Balanced
Unbalanced
Understand fragile sites/hot spots.
Sites that are prime to breakage due to replication stress
purines: larger or smaller?
larger
pyrimadines: larger or smaller?
smaller
Sugar how does it look:
pentagon ish looking thing
Part in DNA that is a circle w two lines connecting to smaller circles on the edge-
Phospherdiester bond
Number of base pairs per turn-
10
Number of bonds per base pair
AT=2; GC=3
elongation
- Primase - This syntehsises short stretches of RNA nucleotides.
- DNA polymerase - DNA polymerase(s) synethsies the leading and lagging strands and removes RNA primers This requires primase to act before because it creates a foundational template for polymerase. It is important to know that it can only add to the 3’ end of DNA.
- DNA liagase - DNA liagase takes care of Okazaki fragments by forming phophodiester bonds between them. Since DNA synthesis can only in the 5’ to 3’ direction, this is where ligase comes in to play.
monohybrid
cross happening in the F1 generation offspring of parents differing in ONE trait only
DNA vs RNA sugar
In DNA, the sugar is deoxyribose, while in RNA, the sugar is ribose.
dihybrid
a cross that happens in F1 generation offspring differing in TWO traits
Griffith’s experiment
Genetic info was passed from dead to living cells. This was called transforming principle
Avery, MacLeod, McCarty
Clear that substance in transforming principle carries genetic info, but what substance carries that info, DNA, RNA, or protein? Result: transforming principle only happened w/DNA present soooo DNA must carry genetic info
Hershey-Chase
DNA is the genetic info in bacteriophage (through color labeling and blending. Which does it spread to bacteria in?)
Base Pairs:
Adenine + thymine
Guanine + cytosine
chromatin
DNA + histone proteins. helps package DNA smaller
histones
the histones are proteins that help support DNA
Euchromatin vs. heterochromatin
Euchromatin
* less condensed
* found on chromosome arms
* has many genes
* has unique sequences
* often transcription
Heterochromatin
* tightly condenced
* found at centromeres, telomeres, and other specific locations
* has few genes
* has repeated sequences
* infrequent transcription
nucleosome
sequence w/eight histones
telomeres
A telomere is a region of repetitive DNA sequences at the end of a chromosome. Telomeres protect the ends of chromosomes from becoming frayed or tangled. Each time a cell divides, the telomeres become slightly shorter.
Centromere
Where sister chromatids connect (this is where kenetichore is located)
chiasmata
a structure that forms between a pair of homologous chromosomes by crossover recombination and physically links the homologous chromosomes during meiosis.
when does crossing over happen
prophase 1
Autopoloploidy
More than two sets of chromosomes often due to failure of cell division. same parent specific
Allopolyploid
more than two sets of chromosomes from two different species (think of a mule)
Nonrecombinent
same as parents
Recombinant
not same as parents
independent assortment
genes are independent of each other (meaning if you get one, you wont necessarily get the other)
linked genes
near each other on a chromosome and thus inherited together more often.
why are worms ideal for genetic models?
- small (and easy to acquire and manage)
- short-lived (makes it easier to study faster)
- around 70% genetically similar to humans
leading strand
going to be continuous. 5’ to 3’.
lagging strand
fragments w polymerase. opposite direction as replication fork
