Download Science 24 Tutorial – November 13th

Science 24 Tutorial – November 13th
A reminder to everyone to mark Monday December 8th on your calendar. From 1-3 pm,
there will be a lab in Airdrie that everyone is expected to attend. Although there is not a
final exam in Science 24, everyone is expected to attend this lab session in its place.
For U3L2, you will need to do some research on a pathogen (pg. 164)…anthrax,
smallpox, meningitis etc. which you will need to present in our next tutorial. Make sure
that you bring it with you to our next tutorial.
We started unit 3 on Disease Defence and Human Health this week. In this unit you will
learn about causes of human disease, communicable and non-communicable diseases,
and factors that influence your chances of getting a disease. You will learn about
pandemic and epidemic diseases and the role of public health. You will also learn about
your body's defence against pathogens, types of immunity, immunization, and how to
treat diseases. We will wrap up the unit learning about genetics, inheritance, how to use
the Punnett square and pedigrees to predict the passing of traits through generations, as
well as genetic diseases and issues in genetic research. I think you will find this unit very
interesting!
Let’s begin with some discussion about disease.
• Ask students to study the photograph of the student coughing and discuss how colds
(e.g., symptoms, treatments) can affect their activities. Make a connection with the
photograph of the virus that causes colds. Have students consider how diet, lifestyle,
and environmental factors might lead to a cold.
• Use the white board to list diseases (e.g., flu, strep throat) that students have had. Ask
students who are willing to share their knowledge or experience.
– Can the disease spread from one person to another?
– How does the disease spread?
– What lifestyle factors might affect how often someone gets sick or how quickly they
recover from illness?
Ans. preventive actions (e.g., balanced diet, regular exercise, updated immunizations,
brush teeth (prevent gingivitis)) they take at home, at school, and/or at work to avoid
getting sick or spreading disease to others. Make a list .
What about food poisoning? How can it be prevented?
Ans. Keep foods that need to be refrigerated in the fridge. Eat hot meals hot and cold
meals cold. Don’t leave sitting out at room temperature.
Disease prevents the normal functioning of the body and is caused by microbes which are
called pathogens or germs. Most pathogens are microscopic. Can you think of what
some pathogens might be?
Ans. Bacteria, viruses, fungi, and protists.
Some diseases are caused by a poor environment. What could be in your environment
that could cause you to get a disease?
Ans. Pollution in lungs – lung disease
Radiation – different types of cancer.
Refer to figure 9.3 on page 159. Let’s identify the many factors that can lead to
gingivitis.
Gingivitis causes the gums to become red, become swollen, and bleed easily. There is
usually little or no discomfort. The following factors affect the health of gums.
• Smoking — This is one of the most important risk factors for gum disease because
smoking creates environments that allow periodontal-causing bacteria to live and
reproduce.
• Genetics — Up to 30 percent of the population may be genetically susceptible to gum
disease. Despite aggressive oral care habits, some people may be six times more likely
to develop gingivitis.
• Pregnancy and puberty — During times of significant changes in the body (e.g.,
puberty, menopause, menstruation, pregnancy), gums can become sensitive because
they are affected by hormonal fluctuations.
• Stress — This makes it more difficult for the body to fight infections.
• Medication — Some drugs, such as oral contraceptives, can affect dental health.
• Poor nutrition — A poor diet makes it harder for the body to fight infections.
• Poor dental hygiene — Regular brushing and flossing of teeth prevents diseases such as
gingivitis.
Bacteria reproduces rapidly in an ideal environment. What do you think this environment
includes?
Ans. Warm temperatures, moisture (need water to reproduce), and food (sugar, protein,
fat). Since we know that bacteria thrive in this environment, what can be done with foods
to prevent spoilage?
Ans. Refrigerate or freeze food, remove water. See table 9.3 on page 168.
Note however that staph bacteria which can cause food poisoning can enter food when
you cough, sneeze, or handle food without washing your hands properly. (Read Did you
Know on page 163).
Viruses – much smaller than bacteria. Cause common cold. They take over cells in the
body to reproduce and quickly multiply. (eg. HIV virus)
Point out to students that HIV causes some people to develop AIDS. Explain that
AIDS is commonly transmitted both by sexual interplay and sharing needles. It can also
be transmitted from mother to child before or during the delivery of a baby or through
breast milk. Originally, one common way to contract AIDS in North America was
through blood transfusions of contaminated blood. This is less common today.
Point out that it is rare to get AIDS from exposure to infected tears or saliva
because these fluids contain very low concentrations of the virus. There are no known
cases of transmission of AIDS through mosquitoes or other animals.
Today, there is no known cure for AIDS. Most deaths are caused by infections
that break down the body’s immune system rather than by the AIDS disease itself.
Does anyone know what a protist is?
Ans. Single-celled organisms that share some characteristics with both animlas and
plants. Eg. Giardia lives in intestine of infected humans (from water what has been
contaminated with the feces from another human or animals.
Fungi includes molds, yeasts, and mushrooms. Some fungi are parasites and can
live only on hosts organisms. Discuss fungi. Tell students about the symptoms of
athlete’s foot — some students may suffer from it. The symptoms include cracked and
peeling areas between the toes, itching, a burning sensation, and blisters that ooze clear
fluid. To prevent this condition, students should avoid wearing shoes made of plastic or
of materials that have to be treated to keep water out. Such shoes trap perspiration and
create warm, moist places for fungi to grow.
Refer to pg. 158.
Louis Pasteur — This scientist made many contributions to microbiology and medicine.
He discovered that microbes cause disease and that weakened forms of a pathogen could
be used to immunize against the pathogen. Pasteur also developed the process we call
pasteurization to destroy pathogens in wine and milk (all milk sold today is pasteurized),
and he developed techniques to vaccinate animals against rabies and to treat humans
bitten by infected animals. Pasteur recommended changes in hospital practices to control
the spread of pathogens.
Robert Koch — This bacteriologist identified pathogens that cause disease. He and his
colleagues identified more than 20 pathogens responsible for diseases such as
tuberculosis, typhoid, diphtheria, tetanus, meningitis, plague, influenza, cholera, and
anthrax. Koch discovered that bacteria could spread from one person to another. He also
developed techniques for studying and culturing bacteria. For example, he developed a
gelatin beef-broth solution to culture bacteria. Now known as agar, this solution is used
worldwide today. One of Koch’s assistants — Petri — invented the petri dish.
What is the difference between a communicable and non-communicable disease?
Communicable – contagious (Examples? Cold, flu, AIDS)
Non-communicable – Not caused by pathogens…not contagious. (diabetes, cancer)
How can communicable diseases be spread?
(Ans. Airborne, water-borne, carried in food, direct contact) (Refer to table 9.1 on page
163).
Diseases that have been linked to poor lifestyle choices include obesity among
teens, liver disease, eating disorders, some cancers, emphysema, and STDs.
Many environmental pollutants such as smog, chemicals, and other toxins cause
disease. Smog is a combination of fog and smoke that may result in poor air quality. A
smog alert warns people who are at risk — such as the elderly or those who suffer from
heart or lung problems — to stay indoors. High levels of exposure to air pollutants may
lead to respiratory failure, lung disease, or cancer.
Genetic factors are associated with diseases such as Down syndrome, muscular
dystrophy, cystic fibrosis, and multiple sclerosis.
Why do you think living in poverty is one of the most significant determinants of
disease?
Ans. Poor often do not eat enough good food to provide their bodies with nutrition
needed to fight off infection. Sanitation may be poor and increase the chances of
infection. Good medical care may not be available.
To minimize your chances of getting sick, it is important that you live in a clean
environment. Clean environments reduce the number of viruses and bacteria present and
therefore decreases your chances of getting sick. You may have heard of Florence
Nightingale whoreduced the death rate in hospitals by making sure the hospital and
patients were kept clean.
What does the term “aseptic” mean?
Ans. Clean…free of pathogens. Refer to page 170 to review aseptic practices used
today.
Pg. 172 …Review. #1.