-
The 5' end of DNA consists of:
A free phosphate or hydroxyl on the no. 3 carbon of the sugar
-
The 3' end of DNA consists of:
A free hydroxyl group on the no. 3 carbon
-
The sugar moiety in RNA is:
ribose
-
DNA is replicated by __________ replication
semiconservative
-
Elongation by DNA polymerase can only occur from ___' to ___'
5' to 3'
-
Messenger RNA represents the ______ of a segment of DNA
Transcription
-
There are ____ possible codons for ____ amino acids
-
To synthesize a protein the mRNA must be _____
translated
-
transfer RNAs:
Carry an amino acid
-
Biological definiton of a gene:
A trait or character which can be shown to have a simple pattern of inheritance
-
Molecular definition of a gene:
A specific sequence of DNA which codes for a particular protein, polypeptide or RNA sequence
-
The typical sturcture of a gene consists of:
a promoter, start codon, stop codon, regulators (enhancers), exons, and introns
-
A diploid genmore consists of approximately _______base pairs
6 billion
-
Less than ___% of the genome encodes proteins or peptides
10%
-
The current consensus is that there are a total of ______-_____genes
30,000-35,000 genes
-
What is the rest of the genome?
Approimately 90% consists of __________
About 75% consists of ________
The remainder once called _____
About 10-15% consists of_____
Unique or families of related sequences
Single copy DNA-Pseudogenes
Junk DNA
Tandemly repeated sequences-Satellite DNA
-
Each Chromosome is belived to consist of:
A single double helix that forms a complex with nucleoproteins and represents packaging of genetic material, seen in non dividing cells as chromatin
-
An average chromosome unwound is about ____ long
2 meters
-
Each chromosome is about ____ to ____ the length of its constituent DNA
1/3,000th to 1/10,000
-
When packaged DNA is coiled around a ____ to form a string of bead-like _____
histone core
nucleosomes
-
Each nucleosome consists of
an octamer of four differnt histones-2 copies of each
-
The four types of nucleosomes:
H2A, H2B, H3 and H4
-
Approximatley ___bp of DNA are wrapped around each nucleosome seperated by a ___ bp spacer
140
20-60
-
Solenoid
a 30nm chromatin fiber resulting from secondary coiling of nucleosomes
-
Solenoid fibers appear to be organized by attachment in the form of:
loops to a non-histone protein scaffold
-
Telomeres and gene-rich regions have a high ____content
GC
-
Centromeres and gene-poor regions tend to be ____ rich
AT
-
Constitutive heterochromatin
Regions of the genomre that are genetically inert and remain condensed in interphase
A permanent feature of the chromosome
Reflected by a dif in staining of a particular chromosome region in both homologs
-
Facultative heterochromatin
Regions of the genome that are genetically inert due to dosage compensation
herterochromatin associated with inactive X
Not a permanent feature of the chromosome
Does not effect banding pattern
-
Single copy sequences make up ______ of the genome
and ____ are translated into peptides or proteins
- make up more than half of the genome
- only 3%
-
Dispersed repeated sequences make up approximately ___% of the genome and consits mainly of
10%
Alu (SINES, 300bp in length) and L1 or Kpn (LINES, 7-8 bp in lenght)
-
LINES/L1 sequences correspond mainly to ______ or _____ and stain ____by these techniques
G banding or Q banding and stain dark or moderately birght
-
Short tandemly repeated sequences make up ~ ____ of the genome
These include:
- 10-15%
- Satellite DNAs
- microsatellite sequences
- minisatellite sequences
- telomeric sequences
-
SINES/Alu sequences correspond mainly to _____ or____by ___and ___ banding
Dark R bands or bands that stain pail by Q and G banding
-
Transposable elements:
When LINES and SINES generate copies of themselves and insert them elsewehere in the genome and alter gene expression to cause disease
-
Satellite sequences are variably staining and are typically in the _____ regions of the chromosomes
Pericentromeric
-
_________ are polymorphic markers that are heritable and used to map or ID genetic disorders by linkage, can identify genetic fingerprint
Microsatellites and minisatellites
-
Telomeric sequence
Highty conserved and stablizes the ends of chromosome arms (prevent the gradual loss of DNA)
-
Five phases of mitosis
- Prophase
- Prometaphase
- Metaphase
- Anaphase
- Telophase
-
Interphase
- Stages G0-S
- Majority of time in this phase
- Chromosomes not individually visible
-
-
G1
Protein synthesis; prep for S
10-12hours
-
-
-
-
The lenght of the cell cycle is ___hours
16-24
-
Metaphase is ____ long
and is the period in which chromosomes are ______
- Mose condensded and easily distinguishable under the microscope
- Usually consist of 2 chromatids attached at the centromere
-
The division of centromeres marks the begining of
Anaphase
-
________ can inhibit the division of centromeres by disrupting the formation of microtubules
Colchicine
-
The DNA content in G1 is:
2n
-
The DNA content in S is
2-4n
-
-
-
Daugter cells each have ____ of DNA
2n
-
Telophase
Cell membrane begins to reform around each set of chromatids
-
A birth the ova have already initiated ______ which remains in a suspended state of_____ until fertilization
First meiotic cell division
prophase
-
in males, first and second meiotic cell division resutlting in the formation of sperm occur at ______ and spermatogenesis is:
Peuberty
ongoing througout reproductive life
-
Leptotene
- The initial pairing of paternal and maternal chromosomes
- very percise
-
The end of the pairing of maternal and paternal chromosomes is called
zygotene
-
Synaptonemal complex
the structure holding the chromosomes together during pairing
-
Pachytene
the stage at which the chromosomes start to seperate in meiosis
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