Alcohol March 2015. Yeast and Alcohol For thousands of years, people have used a fungus called...
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Alcohol March 2015. Yeast and Alcohol For thousands of years, people have used a fungus called baker’s yeast, Saccharomyces cerevisiae, to ferment ethanol
Yeast and Alcohol For thousands of years, people have used a
fungus called bakers yeast, Saccharomyces cerevisiae, to ferment
ethanol (drinking alcohol) and bake bread. The bubbles in
champagne, for example, owe to the activity of this yeast. When
yeast are causing bread dough to rise, do they also make
alcohol?
Slide 3
Fermentation When glucose is broken down by glycolysis, the
electron carrier NAD + is converted into NADH. This NADH can be
used in the electron transport chain to make ATP if oxygen is
available. But what about when theres no free oxygen available? In
that case, the organism needs to recycle the NADH back to NAD + !
In addition, there needs to be a way to get rid of the pyruvate. In
yeast, this is done by making carbon dioxide and ethanol the
bubbles and alcohol in alcohol fermentation. These bubbles are also
what causes bread dough to rise.
Slide 4
Distillation Once yeast make enough alcohol to raise the
concentration to about 15%, they stop fermenting; too much alcohol
would kill them. To make drinks with a higher percentage of alcohol
than that, we use distillation. Because alcohol evaporates more
easily than water, heating an alcoholic drink and capturing the
steam will separate it from water. (Note: Improper distillation
carries a risk of explosion.)
Slide 5
Proof and Percentage Alcohol Concentration As a general rule,
which, if any, of the following contains the most alcohol? A 12 oz.
can of beerA 5 oz. glass of wineA 1.5 oz. shot of whiskey
Slide 6
Proof/Percentage Alcohol by Volume Because the beer has the
lowest concentration of alcohol and the whiskey has the highest
concentration of alcohol, but a single drink of whiskey is smaller
than a can of beer all three servings have about the same total
alcohol content. By and large, an alcoholic drink is an alcoholic
drink; wine is only safer in that people may drink it more slowly
than shots. Alcohol content can be measured in percentage by volume
or by proof. Proof is just twice the percentage by volume. If a
drink is 50% alcohol, it is 100 proof. Proof is not a measure of
quality. Even high proof beverages can contain impurities that
increase hangover pain, and some can have a deceptively mild taste,
making it easy to become intoxicated quickly without realizing the
high alcohol content. Drinking cups not specifically meant for a
given drink do not take proof into account. Be careful when
drinking from large cups.
Slide 7
Blood Alcohol Concentration (BAC) What is the legal limit for
Blood Alcohol Concentration for driving in most U. S. states? A)8%
(8/100 of your blood is alcohol) B).8% (8/1000 of your blood is
alcohol) C).08% (8/10,000 of your blood is alcohol) D).008%
(8/100,000 of your blood is alcohol) Assuming no problems with
alcohol metabolism, how many drinks would it take a 140-lb woman to
reach this level? What about a 220-lb man?
Slide 8
Blood Alcohol Concentration
Slide 9
Safer Drinking Habits Always have a designated driver at events
that involve alcohol. Do not drink too much at one occasion. Very
generally, binge-drinking is defined as >4 drinks within 2 hours
for men, or >3 drinks within 2 hours for women. Never drink on
an empty stomach; food slows down the rate of alcohol absorption
and reduces the risk of alcohol poisoning. Avoid drinking games,
and never drink to unconsciousness.
Slide 10
What Causes Hangovers? Which of the following play a role in
hangovers? Choose all that apply: A)Dehydration B)Poisonous
molecules the body makes from alcohol C)Poisonous molecules found
with alcohol in drinks D)Low blood sugar Will coffee reduce the
symptoms of a hangover?
Slide 11
Alcohol Metabolism Alcohol dehydrogenase (ADH) converts ethanol
into poisonous acetaldehyde, which is 20 times more toxic than
alcohol itself. This happens mostly in the liver, but also in the
stomach lining, where alcohol is absorbed. The acetaldehyde
dehydrogenase enzyme (ALDH) then converts the acetaldehyde into
relatively harmless acetate (same stuff as vinegar) in the liver.
People without a working ALDH enzyme are highly sensitive to
alcohol and can suffer brain damage quickly from alcohol
consumption!
Slide 12
Alcohol and the Liver Long-term alcohol consumption damages the
liver. This damage3 can take multiple forms: Fatty liver: Buildup
of fat in liver cells. Can cause inflammation Hepatitis:
Inflammation of the liver; can lead to jaundice and eventually
liver failure. Cirrhosis: Scarring and hardening of the liver.
Eventually can be fatal.
Slide 13
Alcohol and Nutrition Because alcohol is a form of empty
calories, it can displace healthy foods from the diet and lead to
weight gain. In addition, because alcohol is a diuretic, it causes
loss of water- soluble vitamins and minerals, in particular B
vitamins and zinc. Wernicke-Korsakoff syndrome: nerve damage,
paralysis, memory loss brain damage.
Slide 14
Fetal Alcohol Syndrome Alcohol is a teratogen that is to say,
it can cross the placenta and cause birth defects in a developing
embryo in the form of Fetal Alcohol Syndrome, which can affect
facial and brain development. Some studies suggest that very modest
alcohol consumption during pregnancy (1 glass of wine a week) is
harmless. However, the Centers for Disease Control advise caution
in this there is no guaranteed safe amount.
Slide 15
Alcohol Dependency and Abuse Destructive use of alcohol can
lead to dependence. A person begins needing more alcohol to achieve
the same sensation, and suffers withdrawal symptoms, such as
nausea, insomnia, anxiety, or even tremors and seizures when they
go without drinking. Alcohol dependency develops over time, and
cannot be reversed quickly or easily. Support groups, antiabuse
drugs, and therapy can help, but long-term abstinence from alcohol
is always challenging for those who have struggled with alcohol
abuse. Warning signs of alcohol dependency include unsuccessful
efforts to cut down on drinking, reduction in important daily
activities for alcohol use, and episodes of binge-drinking and
hangovers.
Slide 16
Benefits of Red Wine? Some studies suggest that phytochemicals
from the skin of grapes, such as resveratrol, found in red wine,
can have healthy antioxidant effects and reduce the risk of heart
attacks. Our text uses this to explain the French Paradox. The
French Paradox is that on average, the French eat a diet with a
great deal of cholesterol and saturated fat, yet have lower risks
of heart disease than Americans. They also drink more red wine. Is
this line of reasoning sufficient to conclude that drinking red
wine is responsible for the better health of the French? What else
could be at play here? Given what Ive said above, is there any way
to get the benefits of resveratrol without drinking red wine?