Glucosidase Activity at Various Temperatures 200
150
Glucosidase activity
(mol/L/h)
()
100
50
70
30 40 50 60
80 90
Temperature (°C)
This graph shows the activity of an enzyme called
glucosidase. What can you conclude from these
data?
A. Glucosidase breaks down glucose substrates.
B. Glucosidase functions best around 70°C.
C. Glucosidase does not function below 70°C.
N. Glucosidase is not affected by temperature.

Which of the following is a reason why early living organisms on earth could not have survived on the surface? 1. the lack of an ozone layer 2. the lack of oxygen in the atmosphere 3. the fact that these organisms were single-celled

Astudy by solloch and et. al., in 2017, gives the map above which shows the frequency of alleles with a ccr5-delta32 mutations over 87 different countries. this mutation deletes the presence of a co-receptor (ccr5) on the outside of human t-cells (lymphocytes). some viruses, such as the one responsible for the black death and human immunodeficiency virus (hiv), require this receptor for attachment to host cells during the infection process. the black death was an epidemic that passed over northern europe during the 14th century killing nearly 60% of europeans. according to this information, which explanation best explains why northern europeans show a greater immunity for hiv than some other parts of the world?

Which one of the following is true of trnas? a) trnas are double-stranded. b) each trna binds a particular amino acid. c) there are four types of trna. d) trnas carry special sequences known as codons. e) all of the above