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Cells and Reproduction Lesson Starter 1. Name one type of cell which is specialised to its job. Can you describe how it is specialised? 2. Put the following terms in order of structure• Organism • Cells • Organ • System • Tissue Learning Intentions • To learn about puberty in humans Success Criteria 1. State what the term puberty means 2.State the changes in boys during puberty 3.State the changes in girls during puberty Humans are only able to reproduce after their bodies go through changes and they reach SEXUAL MATURITY. We call the onset of sexual maturity PUBERTY. Working in pairs, write down the changes boys and girls go through during puberty. http://www.twigonglow.com/films/introduction-to-puberty-1023/ Changes for Boys Voice deepens Grow hair on face and chest Grow pubic hair Sexual organs get bigger Start producing sperm Shoulders broaden Hormones produced http://www.twigonglow.com/films/puberty-in-boys-1025/ Changes for Girls Breasts grow bigger Egg released once per month by ovaries Grow pubic hair Sexual organs get bigger Menstruation begins Hormones produced http://www.twigonglow.com/films/puberty-in-girls-1024/ Puberty Before humans can ________ they must reach sexual maturity. The process where a human’s body changes so it is able to reproduce sexually is called ________. Both boys and girls grow _____ hair during puberty. Their sexual organs get bigger and ________ begin to be produced. Boys begin to produce sperm and girls begin ___________. pubic hormones reproduce menstruation puberty Puberty reproduce they must reach Before humans can ________ sexual maturity. The process where a human’s body changes so it is able to reproduce sexually is puberty called ________. pubic hair during Both boys and girls grow _____ puberty. hormones Their sexual organs get bigger and ________ begin to be produced. Boys begin to produce sperm and girls begin menstruation ___________. pubic hormones reproduce menstruation puberty Lesson Starter At the back of your jotter write a paragraph on your model cell. Include the following point: 1. What type of cell you choose to make and why 2. What material you used to make the cell 3. If the materials worked well or if you had to change anything Starter Puberty 1. What is puberty? 2. Who reaches puberty first, boys or girls? 3. Give two changes only boys go through during puberty. 4. Give two changes only girls go through during puberty. 5. Give two changes boys and girls go through during puberty. Exercise 5: Puberty 1. What is puberty? When humans go through changes to reach sexual maturity. 2. Who reaches puberty first, boys or girls? Girls. 3. Give two changes only boys go through during puberty. Grow facial hair, shoulders broaden, begin producing sperm. 4. Give two changes only girls go through during puberty. Breasts get larger, menstruation begins, eggs released from ovaries once per month. 5. Give two changes boys and girls go through during puberty. Grow pubic hair, hormones produced, sexual organs get bigger. Lesson Starter: Label the Diagram Female Reproductive System Oviduct/ Fallopian tube Uterus Ovary Cervix Upon sexual maturity one egg is released from the ovaries every month. Vagina Female Reproductive System Oviduct/ Fallopian tube Uterus Ovary Cervix Upon sexual maturity one egg is released from the ovaries every month. Vagina The Female Reproductive System Female reproductive system Organ Uterus Oviduct/ Fallopian tube Ovary Vagina Function Female reproductive system Organ Uterus Oviduct/ Fallopian tube Function A muscular sac where a baby develops Tubes which carry the egg from the ovary to the uterus Ovary Produce the eggs and female hormones Vagina A muscular tube that opens to the outside of the body Lesson Starter 1. What is the function of the uterus? 2. What is the function of the ovaries? 3. What is the function of the fallopian tubes? 4. Can you remember where the sperm and the egg meet (fertilisation)? Male Reproductive System Urethra Gland Sperm duct Penis Testes Upon sexual maturity sperm begins to be produced. Male Reproductive System Upon sexual maturity sperm begins to be produced. Lesson Starter 1. What is the function of the testes? 2. What is the function of the sperm duct? 3. What is the function of the scrotum? 4. Can you describe how a sperm cell is well suited to its job? Male Reproductive System Urethra Gland Sperm duct Penis Testes Upon sexual maturity sperm begins to be produced. The Male Reproductive System Male reproductive system Organ Function Sperm Duct Connects to the urethra and carries sperm away from the testes. Testes Produce sperm and the male hormone testosterone. Penis Carries urine and sperm out of the body. Scrotum The sac in which the testes are held. Exercise 6: Which Labels Are Correct, Which Are Wrong? Sperm duct x Uterus Ovary Vagina Exercise 7: Which Labels Are Correct, Which Are Wrong? Urethra Gland Oviduct x Ovary x Uterus x Testes Cervix x Lesson Starter 1.Draw and label the parts of a sperm cell 2.Draw and label the parts of an egg cell Sex cells - Sperm In males the sex cells are called sperm. Sperm are produced in sex organs called testes. Nucleus containing chromosomes Tail Middle piece http://www.twigonglow.com/films/sperm-929/ Cell membrane Head Sex cells - Eggs In females the sex cells are called eggs. Eggs are produced in sex organs called ovaries. Nucleus containing chromosomes cytoplasm membrane jelly coat An egg is so big that this is how big a sperm looks next to it. http://www.twigonglow.com/films/egg-930/ Sperm or Egg? Fertilisation: Fusion of a male & female sex cell (gamete) http://www.twigonglow.com/films/fertilisation-931/ The nucleus of the sperm cell (male gamete) fuses with the nucleus of the egg cell (female gamete) Lesson Starter 1.What does the term fertilisation mean? 2.Draw what you think this process would look like? 3.What happens after fertilisation takes place? Fertilisation in animals Once fertilisation has taken place, the new cell (which is called a zygote) starts to divide, multiply and grow in size, eventually producing a new baby. Where does the fertilisation take place? Internal fertilisation Menstruation Once every 28 DAYS an EGG is released from the ovaries. It travels down the OVIDUCT towards the UTERUS. Every month the walls of the uterus thicken up in preparation in case the egg is FERTILISED. If the egg is UNFERTILISED the walls of the uterus break up and pass from the body through the VAGINA along with the unfertilised egg. This is called the PERIOD and can last 3-4 DAYS. If the egg is fertilised then it EMBEDS itself in the uterus wall and will begin to develop into a new individual. Menstruation Once every ovaries. It travels down the an is released from the towards the . Every month the walls of the uterus thicken up in preparation in case the egg is . If the egg is the walls of the uterus break up and pass from the body through the along with the unfertilised egg. This is called the and can last . If the egg is fertilised then it itself in the uterus wall and will begin to develop into a new individual. Lesson Starter 1. How often is an ovum released from the ovaries? Every 28 days. 2. How long does a period last? 3-4 days. 3. What connects the ovaries to the uterus? The oviduct. 4. What happens to the uterus in preparation for a fertilised ovum? The walls become thicker. 5. How does the unfertilised ovum and the broken-down walls of the uterus leave the body? Through the vagina. A Womb with a View • In the beginning sperm joins with ovum (egg) to form one cell - smaller than a grain of salt. • This union brings together the 23 chromosomes from the father with the 23 chromosomes from the mother to make a single new life with 46 chromosomes - the genetic blue print for the development of every detail this new person will ever have. • For the next few days the fertilized egg travels down the fallopian tube into the uterus. • At the end of the first week it implants itself into the lining of the uterine wall and draws nourishment from its mother. • From Days 1014 the developing embryo signals its presence through placental chemicals and hormones to the mother’s body telling it to cease menstruation. • By only Day 20 foundations of the brain, spinal cord and nervous system are already established. • By Day 21 the heart begins to beat. • By the 4th week, the backbone and muscles are forming. Arms, legs, eyes, and ears have begun to show. • Now one month old, the embryo is 10,000 times larger than the original fertilized egg and is developing rapidly. • At Week 5 five fingers can be discerned in the hand. The eyes darken as pigment is produced. • Brain waves can be detected and recorded. • At Week 6 the liver is now taking over production of blood cells, the brain begins to control muscle movements and organs. • Week 7 - The embryo begins to move spontaneously. The jaw forms, including teeth buds in the gums. • Soon the eyelids will seal to protect the embryo’s developing lightsensitive eyes, and will reopen at about the seventh month. • By the 8th Week the nowcalled fetus is a little more than an inch long. The fetus has now everything found in a fully developed adult. • The heart has been beating for more than a month, the kidneys are functioning; the stomach is producing digestive juices. • And it responds to touch. • At Week 9 the tiny one has fingerprints and will curve its hand around an object placed in its palm. • By Week 10 the fetus can squint, swallow, and wrinkle its forehead. At the 11th week, the fetus is now about 2 inches long. Urination occurs. Muscle movements are becoming more coordinated. 3m • Now 3 months old, the unborn sleeps, awakens, and exercises its muscles. It “breathes” amniotic fluid to help develop its respiratory system. Fine hair is growing on the head. 4m • At 4 months the fetus is 8-10 inches long and weighs half a pound. • The mother starts to “show.” The baby’s ears are functional. • It can hear its mother. • The fetus at 5 months is now about 12 inches long. There is definite movement felt by the mother. The unborn may jump in reactions to startling or loud noises. • At the 6th month oil and sweat glands are now functioning. The delicate skin is protected from the fetal waters by a special ointment called “vernix.” Born now and given proper care, the baby would survive… • At 24 weeks, this unborn child was operated on for spina bifida while still in the uterus. • This is Sarah Marie Switzer, the baby who was operated on above. • This is about the time that a premature baby can survive outside the womb, given proper medical treatment. • This little boy, here 7 weeks after birth, was born when his mother was only 25 weeks pregnant. • At Month 7 the baby now uses the four senses of hearing, vision, taste, and touch. The child can respond to his or her mother’s voice. • In the 8th month the skin begins to thicken with a layer of fat stored underneath for insulation and nourishment. Antibodies increasingly build up. • The baby is nearly ready for life outside the womb. • Toward the end of this month the baby is ready for birth. By this time the infant normally weighs 6 to 9 pounds, and his or her heart is pumping 300 gallons of blood per day. Any questions? Lesson Starter 1. What does the embryo use to signal to the mother to stop menstruation in days 10-14? 2. In what week does the embryo begin to move? 3. In what month does the mother start to ‘show’? 4. In month 6 what is ‘vernix’ important for? 5. After how many months is the baby ready for life outside the womb? Lesson Starter 1. What is the name of the cord that attaches the mother to the embryo? 2. What is its role? 3. What is the embryo surrounded in when inside the uterus? 4. What happens to this before labour? Pregnancy • During pregnancy the ball of cells in the womb lining slowly grows into tissues and organs Amniotic fluid Placenta http://www.twigonglow .com/search/alt/?q=pr egnancy Embryo Uterus wall Umbilical cord Placenta Supplies nutrients to baby and removes waste materials. Amniotic fluid Acts as a shock absorber to protect the baby and placenta before birth. Amniotic sac Contains the amniotic fluid and protects the baby. Umbilical cord Connection tube from placenta to baby for exchange of materials. Part Placenta Amniotic sac Amniotic Fluid Umbilical Cord Function Supplies nutrients to baby and removes waste material Contains the amniotic fluid and protects the baby Acts as a shock absorber to protect the baby and placenta before birth Connection tube from placenta to baby for exchange of materials Stage 1: contractions begin The baby turns around its head facing the vagina. The uterus wall begins powerful contractions and the amniotic sac bursts (commonly referred to as the waters breaking). Stage 2: uterus opening expands The vagina dilates allowing the baby’s head through. If the baby has not turned around and the head is not at the opening of the vagina it is known as a breech birth. Stage 3: head appears Once the baby is born the umbilical cord is cut and further contractions allow the remains of the placenta and umbilical cord to exit the vagina. Lesson Starter 1. What is the function of the placenta? 2. What is the function of the umbilical cord? 3. What is the function of the amniotic sac? 4. What is the function of the amniotic fluid? 5. What must happen before the baby is about to be born? What is your DNA?? http://www.twigonglow.com/fil ms/what-is-dna-1049/ Learning Intentions To learn about the role of DNA Success Criteria 1. Where is DNA found? 2. What structure is DNA located on? 3. How many chromosomes does a human have? 4. What chromosomes determine if we are to develop into a boy or a girl? Chromosomes • The nucleus of a cell contains the instructions for that organism • These instructions are carried by chromosomes • Chromosomes are thin thread-like structures • Every normal cell in a human body has 46 chromosomes Chromosomes • Chromosomes are found in the nucleus of cells. • Every normal cell in a human body has 46 chromosomes Human chromosomes • The 46 chromosomes are actually 23 pairs • 1 of each pair has come from the mother and the other has come from the father Chromosomes • Sperm cells and egg cells produced contain only 23 chromosomes • When a sperm and an egg fuse, the newly fertilised egg has a complete set of instructions to develop into a baby ( 23 + 23 = 46) Number of Chromosomes 23 Fertilisation 23 Division 46 46 46 What makes us male or female? • Our 46 chromosomes are arranged as 23 pairs. • Pair number 23 are our sex chromosomes and determine if we are male or female. What are little girls made of? •XX What are little boys made of? •XY What is the sex of the following individuals? male female Genes • Chromosomes are chains of individual pieces of information called genes • A gene is a section of chromosome which contains a separate piece of genetic information Fertilisation Sperm egg Zygote 2 cells Zygote 8 cells 4 cells We’re from our dad!! We’re from our mum!! I contain my dads genes I contain my mums genes Brown wavy hair, a button nose, brown eyes and Brown straight hair, a little pointy nose, hazel eyes and pale skin Sallow skin And lots more that you can’t see!! And lots more that you can’t see!! A gene for a characteristic is at the same place on a chromosome. Blue eyes Brown skin Dad Brown eyes Mum Pale skin Species Geranium Pea Barley Turnip Tomato Fruit fly Toad Human Chimpanzee Cow Chromosome complement 10 14 14 20 24 8 36 46 48 60 Lesson Starter 1. What is a gene? 2. Where do you inherit your genes from? 3. If my dad gave me a dominant gene for long eyelashes and my mum gave me a recessive gene for short eyelashes, what length would my eyelashes be? Risk factors to the embryo Task Discuss in pairs what factors you think might be harmful to an unborn baby. Risk factors to the embryo Factors that can be controlled by the mother: Smoking Alcohol Drugs All will be present in the mothers blood and passed from the mother to the baby through the placenta. They will cause difficulties in the babies growth and general health. Risk factors to the embryo Genetic factors: UV light X – Rays Age of mother All can alter the information that is passed from the mother and father to the baby. 1. State a relationship between the age of a mother and the change of having a Down’s Syndrome baby. Down’s syndrome Down's syndrome is one of the most common genetic causes of learning disability. Around 750 babies are born with the condition each year in the UK. People with Down's syndrome share a number of physical characteristics. Not everyone will have all of them, but they may include: •reduced muscle tone which results in floppiness •a small nose and flat nasal bridge •a small mouth •eyes that slant upwards and outwards •a big space between the first and second toe •broad hands with short fingers •their palm may have only one crease across it •a below average weight and length at birth http://www.nhs.uk/conditions/downssyndrome/pages/introduction.aspx Detecting Genetic Disorders Amniocentesis Doctors can take a sample of the amniotic fluid using a needle. The amniotic fluid contains the same cells as the baby, therefore they can be studied for genetic disorders e.g. downs syndrome. http://www.youtube.com/watch?v=bZcGpjyO Xt0