Bio Flashcards
Which muscle fiber subtypes have high mitochondrial density + high capillary density?
Type I (slow twich) and Type IIa (intermediate)
In order for a developing T lymphocyte to become activated and enter into circulation, it must be able to:
Recognize a self-MHC and not become activated by a self-antigen
In order for a bacteriophage (virus) to infect a wider range of bacteria, what viral genes need to be changed?
Tail fibers (identifies and infects host)
Why do infants have more brown fat than adults?
The electron transport chain is less efficient (releases more heat as fuel is burned)
Infants cannot shiver
A greater surface area to volume ratio makes them more susceptible to the cold
What structures arise from the mesoderm?
Musculoskeletal, circulatory, most excretory systems, the gonads, and the adrenal cortex
What is the normal pH of blood?
Around 7.35 to 7.45
Which of the following contains an RNA replicase enzyme? DNA virus Retrovirus Negative-sense RNA virus Positive-sense RNA virus
Negative-sense RNA virus (the RNA acts as a template for synthesis of a complementary strand, need RNA replicase to make sure complementary strand is synthesized)
Why might damaged nerves repair relatively slow?
A relative lack of ribosomes in the axons (they are located in the soma) means that new proteins must be transported large distances
What is expressivity?
People with the same gene/mutation show different phenotypes (one gets cancer while another one has a different hair color)
What is penetrance?
Is a population measure defined as the proportion of individuals in the population carrying the allele who actually express the phenotype
