Individual Dr. Wells Andrea Hazel Matthew Aaron James Blood Glucose (mg/dL) o minutes 15 minutes 117 128 97 111 96 99 97 116 96 109 95 108 97 Monique 94 30 minutes 146 135 105 99 129 94 128 45 minutes 160 154 101 101 141 83 143 60 minutes 152 143 98 102 139 88 140
Introduction
“Mother’s Milk” is packed with proteins, fats and carbohydrates that support the
growth, development and survival of baby mammals. The sugar lactose is the
main carbohydrate in milk. Lactose can be cleaved into two simpler sugars,
glucose and galactose, by lactase, an enzyme produced in the small intestine. The
two smaller sugars are readily absorbed through the intestinal wall into the
bloodstream for delivery to the cells of the body, where they are used for energy.
After infant mammals are weaned from their mother’s milk, lactase production
shuts down, presumably because it is no longer needed. This condition is called
lactase nonpersistence – meaning the production of lactase enzyme does not
persist into adulthood. The general condition for mammals is not to consume
milk after weaning and to be lactase non persistent. Some populations of
humans are unusual in that adults continue to consume milk form other
mammals, such as cows.
If a person who is lactase nonpersistent drinks milk, undigested lactose passes
from the small intestine to the large intestine where it is fermented by bacteria.
Fermentation produces various gasses in the large intestine, which cause
abdominal pain, bloating, flatulence and diarrhea – all symptoms of lactose
intolerance. Worldwide, most adults are lactose intolerant, although some
people may not know it because their symptoms are mild. Only a minority of
human adults (about 35% of the global human population) continues to produce
lactase into adulthood and can drink milk without any problems. These
individuals are said to be lactase persistent or lactose tolerant.
There are several ways to test whether someone is lactase persistent. In the short
film, Got Lactase? The Co-evolution of Genes and Culture, the narrator, Dr.
Spencer Wells, takes a blood glucose test to deduce his lactase status.what im asking you to do is
examine the results of the blood tests conducted on six different
adults to determine who is lactase persistent (lactose tolerant) or lactase
nonpersistent (lactose intolerant).
Procedure
STEP 1: Examine the data in the table below. It shows the blood glucose levels of six
individuals tested in Dr. Sarah Tishkoff’s laboratory. After baseline (i.e. time 0
minutes) blood glucose levels of six individuals were measured and recorded,
Each person drank a liter of milk. Blood glucose levels were again measured at
15, 30, 45 and 60 minutes after drinking the milk. Glucose levels were measured
using glucose strips and a glucose reader.
(table is posted belo)
Step 2. Plot the results from the seven individuals on a graph.
Label your axes with units; provide a legend and a title.
STEP 3: Identify the dependent and independent variables.
(The two main variables in an experiment are the independent and dependent
variable. An independent variable is the variable that is changed or controlled
in a scientific experiment to test the effects on the dependent variable.
A dependent variable is the variable being tested and measured in a scientific
experiment.
When results are plotted in graphs, the convention is to use the independent
variable as the x-axis and the dependent variable as the y-axis.)
Step 4: (answer questions)
1. Identify the time interval when blood glucose levels of participants are highest.
2. Calculate the difference in Andrea’s blood sugar from her baseline to the 30
minute interval.
3. Based on these results, make a prediction about the lactase persistence and
nonpersistence of the participants.
Organize the participants into two groups in a table – persistence and
nonpersistence.
4. Identify the group that you predict the Maasai population of Kenya would fall
into. Justify your choice.
Step by step
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