BIO2581 Section 11

An alien species uses 8 bases in their DNA systems. Through advanced sequencing technology, scientists have figured out they have a single stranded genome of 2000 nucleotides. How many times would you expect a friends of 3 randomly chosen nucleotides to appear in their genome?

• 0.25
• 4
• 31
• 0.03
• 8

Which of the following organisms has the greatest amount of non-coding DNA?

• A bacteria with a 1.2Mbp genome, facing high selective pressure for replication.
• A human with a 3 Gbp genome, facing low selective pressure for replication.
• A lungfish with a 130 Gbp genome, facing low selective pressure for replication.
• A yeast cell with a 200 Mbp genome, facing high selective pressure for replication.
• A flowering plant with a 130 Gbp genome, facing high selective pressure for replication.

You sample a bacterial strain with the beta galactosidase expression genotype Ie Oc Z-/I- O+ Z+. The negative (-) indicates a loss of function allele, the c indicates a constitutive operator mutant allele, and the positive (+) indicates a wild-type allele. The e is an unknown allele. In the presence of lactose and no glucose, there is no expression of beta galactosidase. In the presence of glucose and no lactose, there is also no expression of beta galactosidase. With this information, classify the missing allele.

• Wildtype
• Gain of Function
• Loss of Function
• Hypomorphic
• Dominant Negative

You have a species of orchid that produces a pink pigment regulated by the gene pink1. You grow an orchid plant and find that all the flowers grow to be white. You grow another plant and discover that it produces a light pink pigment. What best defines the alleles involved in plant and plant 2?

• Hypomorphic a d dominant negative
• Loss of function and gain of function
• Dominant negative and gain of function
• Amorphic and hypomorphic
• Hypomorphic and haplospinsufficient

(see image for question)

• hypomorphic
• null
• amorphic
• gain of function
• dominant negative

Imagine a gene, nfg, that codes a protein that contributes to fur growth in cats. A recessive loss-of-function mutation, nfg1, results in normal fur growth when heterozygous, and patchy fur growth when homozygous. If we find a cat with a dominant gain-of-function mutation, nfg2, in that same gene, what will be the phenotype of the cat?

• Gain-of-function mutations do not always cause the gain of a trait, so the phenotype could be either a gain in fur growth, or a loss in fur growth.
• The cat will have an excess in fur growth.
• The cat will have zero fur growth.
• We don't know if the nfg gene is haploinsufficient, so we can't predict what the phenotype will be.
• We can never predict what a given mutation will do to the phenotype without testing it.

CRISPR-Cas 9 is widely used as genome editing tool due to its ability to introduce double stranded DNA breaks at a specific locations. However, scientists have modified Cas9 to create a version that cannot cut DNA but can still bind to a target sequence. What is the most likely application of this modified Cas9 protein?

• It allows for permanent gene deletion without the need for additional modifications
• It can be fused to other proteins to regulate gene expression at specific locations
• It improves the accuracy of CRISPR by preventing guide RNA mismatches
• It enhances homologous recombination by increasing the frequency of double- stranded breaks
• None of the above