Term
| Separation of homologous chromosomes occurs during which stage of meiosis: |
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Definition
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Term
| The synaptonemal complex develops early in meiosis. It is a lattice of proteins that holds homologues together. Which phase of meiosis would you find it in? |
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Definition
| during pachytene of prophase I of meiosis. It holds homologues together and allows crossing over to take place. |
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Term
T or f
The two strands of DNA must be separated before they can be used as templates? |
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Definition
True
Each strand is used as a template for making a new duplex. |
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Term
| A human female with only one X chromosome is said to have a condition called: |
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Definition
turner Syndrome
Monosomy of the X chromsosome leads to Turner syndrome. |
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Term
| Avery and his coworkers showed the transforming principle as: |
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Definition
DNA
Agents which destroy DNA inactivated the transforming principle. |
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Term
true or false?
in dna the reading of the code occurs without any punctuation? |
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Definition
true
There are no commas in the genetic code to say where one codon ends and the next begins. Bases are read in groups of 3 beginning with the start codon - this is the correct "reading frame". |
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Term
| Humans who have lost one copy of an autosome are called: |
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Definition
monosomics
A monosomic lacks one of an original pair of chromosomes - a condition called monosomy. |
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Term
| Occasionally, chromosomes fail to separate during meiosis, leading to a condition in which the diploid number is not normal. This phenomenon is called: |
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Definition
Nondisjunction.
Nondisjunction is the failure of chromosomes or chromatids to separate during meiosis. |
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Term
| The enzyme that carries out transcription is |
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Definition
rna polymerase
RNA polymerase synthesises RNA using a DNA template. |
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Term
The most common condition of trisomy, in which three copies of a chromosome are present instead of the normal two, is of chromosome:
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Definition
21
Down syndrome is the most common trisomy in which there are three copies of chromosome 21. |
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Term
| Mutations that consist of a change in one or a few nucleotides of a DNA sequence are called |
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Definition
point mutations
Point mutations affect one or a few nucleotides in a single gene. |
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Term
| The sites A, P, and E are progressively occupied by amino acids being assembled into a chain in protein synthesis. These sites are part of |
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Definition
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Term
which disease is this?
It causes neural degeneration:Symptoms do not appear until about age 40:It is an autosomal dominant disorder |
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Definition
HD
Huntington's disease is a late onset, autosomal dominant disorder which causes progressive neural degeneration. |
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Term
| If a mutation occurs in a somatic cell, it passes to |
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Definition
| all descendents of that cell |
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Term
| In sickle-cell anaemia, the defective haemoglobin differs from the normal haemoglobin by: |
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Definition
a single amino acid substitution
Sickle cell anaemia arises from a substitution of glutamic acid by valine at position 6 in the globin chain. |
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Term
| The most common fatal genetic disorder of Caucasians is: |
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Definition
CF
Around 1 in 20 Caucasians are carriers for cystic fibrosis and the frequency of the disease is around 1 in 1600. |
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Term
| ........... is where a cell is committed to a particular developmental fate. Differentiation is where the cell expresses its characteristic set of proteins. |
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Definition
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Term
| ......... ............ genes, such as engrailed, are expressed in a series of 14 stripes in the Drosophila embryo and divide it into 14 segments. |
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Definition
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Term
| ............. are sequences which are not found in mature mRNA and therefore do not code for protein. Not all non-coding DNA, however, is found in introns. |
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Definition
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Term
| The integration of bacteriophage DNA into the bacterial genome is called .............. The integrated genome is called a prophage and the bacterium carrying the prophage is called a lysogen. |
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Definition
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Term
| The ........... is the binding site for a repressor protein which prevents transcription by blocking the promoter. |
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Definition
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Term
| RNA polymerase binds to a site on DNA called the |
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Definition
promoter
RNA polymerase binds to a sequence of nucleotides called a promoter before initiating transcription. |
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Term
| The initial course of Drosophila development is determined by: |
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Definition
maternal genes
Maternal genes are expressed by the female during oogenesis. They code for mRNAs which are stored in the egg until fertilisation when they are translated and program early development. |
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Term
| Most regulation of gene expression occurs at the .................. level, presumably because it is more energy-efficient (ie energy is not wasted making a mRNA that is not translated). |
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Definition
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Term
| The ............ homeodomain and leucine zipper are all examples of structures found in DNA-binding proteins. |
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Definition
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Term
true or false
in eukaryotic dna The entire molecule has encoded information for protein synthesis?
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Definition
False
Eukaryotic DNA contains many regions which do not code for proteins. Some of these are introns within genes but much non-coding DNA lies between genes. |
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