1.4-1.7 Science Notes PDF

**1.4-1.7** **Words to learn** 1.Oxygen -a colorless gas that makes up part of the air 2.Carbon dioxide -a colorless gas that makes up part of the air; we breathed out during respiration; plants use it in photosynthesis 3.host -the living thing that a parasite infects 4.Bacteria-an organism tha...

**1.4-1.7** **Words to learn** 1.Oxygen -a colorless gas that makes up part of the air 2.Carbon dioxide -a colorless gas that makes up part of the air; we breathed out during respiration; plants use it in photosynthesis 3.host -the living thing that a parasite infects 4.Bacteria-an organism that lives on or in another organism and can cause disease. 5.parasite -tiny organism that can cause infection 6.fungi -living organisms that use food from the environment to obtain energy. 7.Infection- to cause something to pass on form one place to another 8.transmit -a disease or illness. 9.vector -an organism, such as an insect,that transmits a disease or parasite from one animal or plant to another. 10.physical barrier -a barrier that stops germs from entering the body, for example the skin 11.chemical barrier-a barrier that destroys germs on the body surface or openings ,for example mucus 12.mucus -a slimy substance found in the body 13.Microorganisms-or microbes are tiny living organisms that cannot be seen with the naked eye. 14.fertilization -the joining of a male sex cell and a female sex cell 15.hormones -chemicals in the body that cause the body change that happen during puberty 16.menstruation -the release of an unfertilized egg with the lining the uterus 17.ova -female sex cells 18.puberty -the age at which a person becomes able to reproduce 19.reproductive system -the parts of the body that make the sex 20.sperm -male sex cells **1.2 The respiratory system** 1. Function of respiratory system It allows us to breathe in oxygen and breathe out carbon dioxide. 2. Organs Includes the nose, trachea, lungs, and diaphragm. 3. Breathing Process:Involves inhalation (taking in air) and exhalation (expelling air) 4. Diaphragm:Muscle below the lungs that aids in breathing. 5. Respiratory Disorders:Common issues include asthma, bronchitis, and pneumonia. 6. Maintaining Health:Avoid smoking, ensure good air quality, exercise, and practice good hygiene **1.3 The Reproductive System** **Key Facts About Puberty and the Reproductive System** 1.Changes During Puberty: Boys and girls experience changes in their bodies during puberty, especially in the reproductive system.These changes make it possible for boys to become fathers and girls to become mothers when they grow older. Reproductive System\'s Role: The main function of the reproductive system is to produce special cells needed for reproduction.Boys produce sperm (male sex cells).Girls develop eggs or ova (female sex cells). Fertilisation: Reproduction happens when a sperm and an egg join together, a process called fertilization.This creates a new living being that grows into a baby. Boys During Puberty: Boys\' bodies begin to produce sperm during puberty. Girls During Puberty: Girls\' bodies start to develop ova.Menstruation (periods) begins about a year after puberty starts.During menstruation, an unfertilized egg and the lining of the uterus are released from the body,causing bleeding.Menstruation occurs about once a month but may not be regular at first. **Changes in the reproductive system** **Key Facts About Puberty** What is Puberty? Puberty is the stage in life when your body changes, and you become able to reproduce.It starts at different ages for boys and girls:Boys: Around 13 years old.Girls: Around 11 years old. Why Does Puberty Happen? Changes are caused by chemicals in your body called hormones. Growth Spurt: You grow very quickly during puberty: Boys: Can grow up to 10 cm in a year.Girls: Can grow up to 12 cm in a year.Changes in Hair: Boys: Hair grows on the face, armpits, and other parts of the body. Girls: Hair grows in the armpits and other parts of the body. Skin Changes: Skin becomes oily, and many boys and girls get pimples. Changes in Boys: Shoulders and chest become broader.Muscles develop.Voice becomes deeper. Changes in Girls: Hips become wider.Breasts develop.Voice becomes a little deeper. **Male Reproductive System** **The male reproductive organs include: two testes, which produce the sperm (one is called a testis) the sperm duct, which carries the sperm to the penis the penis, which transfers the sperm into the female's body.** **Female Reproductive System** **The female reproductive organs include: ovaries, which produce the ova or egg cells the uterus or womb, where the baby develops oviducts, where fertilization takes place the birth canal, which receives the sperm from the male and through which the baby is born.** **Microorganism** **Bacteria:** Single-celled organisms.Found in various environments.Some cause diseases, while others are beneficial.2.**Viruses:** Not considered living.Replicate by infecting host cells. **Fungi:** Multicellular organisms.Include molds, yeasts, and mushrooms.Play roles in decomposition. **Parasite:** lives on or inside another organism, known as the host Helpful Microorganisms: **Decomposors:**Microbes help clean up nature by breaking down dead plants and animals. This recycling makes the soil healthier for plants to grow. **Good Food Makers:**Microbes are like little chefs making yummy things like yogurt and bread. **Medicine Makers:**They create antibiotics and vaccines to keep us healthy. **Harmful Microorganisms:** Some tiny germs can make us sick with diseases like theflu or a cold.Certain tiny creatures can spoil our food by breaking itdown.Microbes can enter wounds and cause infections **1.4Infectious Diseases** 1. What are Infectious Diseases? They are illnesses caused by tiny germs like bacteria, viruses,and parasites that can be passed from one living thing to another. 2. How Do They Spread? They spread through the air, water, touch, or bugs like mosquitoes. 3\. Common Signs: Symptoms include fever, cough, tiredness, and stomach issues **Mucus** - sticky mucus in our noses, windpipe and other air passages traps germs. Skin - the skin acts as a barrier to stop germs from getting into the body. Acid - acid in the stomach kills any germs in food we have eaten.