Q#1 DNA in cell chromosomes is usually tightly wrapped into dense, complex cylin
ID: 50271 • Letter: Q
Question
Q#1 DNA in cell chromosomes is usually tightly wrapped into dense, complex cylinders. But cells have the capacity to alter such structures so that the DNA strands inside are exposed to the contents of the cell nucleus. What is the advantage to cells of exposing bare DNA?
RNA transcription ’start’ sites can be recognized by proteins
Protein molecules can be made directly from DNA nucleotide sequences without having to produce messenger RNA first
DNA in the compact cylindrical form is unstable and slowly degrades
4. Only bare DNA is subject to mutational change and without mutation evolution can not proceed
Q#2- Which situation is analogous to the effects of a mutated, abnormal HOX gene during embryonic development?
A group of biology students went to their class room but took a French final exam
UK lost to North Carolina in basketball
Nelson Mandela died in South Africa
Flying pigs do not have wings
QUESTION 4
The phenomenon most similar to the way muscles are signaled to contract is
The formation of the fertilization envelope of sea urchin oocytes after sperm contact
Plant meristem cells differentiating into shoots instead of roots
The digestive system of vertebrates is a central tube
Formation of a visual image (a perception) when looking at an object
QUESTION 5
What happened during development that caused your thumb to be located in its ‘correct’ place?
Apoptosis removed surrounding tissue cells to allow the thumbs to develop
Activities of HOX genes instructed cells in the correct locations to start expressing ‘thumb’ genes
Signal molecules arranged in two different concentration gradients ‘told’ cells in the right locations to make thumb components
The developing thumbs were signaled to stop developing sooner than were the other fingers
QUESTION 6
Why is it that almost all large animals have endoskeletons while most small animals such as insects have exoskeletons?
Exoskeletons offer better protection in the environments occupied by most insects
Exoskeletons likely evolved from aquatic animals with scales
Proportional to body mass, an endoskeleton contributes far less to an animal’s weight than does an exoskeleton
Unlike exoskeletons, endoskeletons allow the attachment of muscles
QUESTION 7
Many animals such as kangaroos and ostriches are capable of running long distances while using significantly less energy than would animals such as dogs and cats of similar body weight.
What is the evolutionary ‘trick’ that kangaroos and ostriches use to reduce energy consumption?
Their respiratory systems are more efficient
Their thermoregulatory systems are more efficient
Their leg tendons have a high proportion of elastic tissue
Their leg muscles require less ATP energy to produce the contraction force that’s generated by the same mass of cat or dog muscle tissue
1.RNA transcription ’start’ sites can be recognized by proteins
2.Protein molecules can be made directly from DNA nucleotide sequences without having to produce messenger RNA first
3.DNA in the compact cylindrical form is unstable and slowly degrades
.4. Only bare DNA is subject to mutational change and without mutation evolution can not proceed
Q#2- Which situation is analogous to the effects of a mutated, abnormal HOX gene during embryonic development?
1.A group of biology students went to their class room but took a French final exam
2.UK lost to North Carolina in basketball
3.Nelson Mandela died in South Africa
4.Flying pigs do not have wings
Explanation / Answer
1 RNA transcription ’start’ sites can be recognized by proteins
2. A group of biology students went to their class room but took a French final exam
HOX genes control the type of segmental structures (Eg: limbs) that are going to be formed in a particular segment. Mutations in HOX genes cause replacement of one body segment by another.
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