Cells and reproduction

Transcription

1 Jordanhill School S1 Science Cells and reproduction Name Teacher

2 Learning Outcomes Cells and reproduction Using a microscope, I have developed my understanding of the structure and variety of cells and of their functions. SCN 3-13a I understand the processes of fertilisation and embryonic development and can discuss possible risks to the embryo. SCN 3-14a I can state that a cell is the basic unit of life I can state that living organisms are made up of many cells of different types I know that groups of cells are arranged into tissues, which are organised into organs which are organised into systems I can state that animal and plant cells contain structures called the nucleus, cytoplasm and cell membrane I can state that plant cells also contain structures called the cell wall, chloroplasts and vacuole in addition to those named above I can identify each of these structures on a diagram I can describe the functions of each of the above structures I can state identify all of the main parts of alight microscope and understand how to look at a slide underneath a microscope I know that before living cells can be viewed underneath a microscope they must be stained with a chemical to make the structures clearer I can state that a specialised cell is one that has a specific job in the body I can give 4 examples of specialised cells and can describe some of the special features they have to help them to do their job I can identify the main parts of the male and female reproductive system and can describe the function of each I can state that the male sex cell is a sperm cell and a female sex cell is an egg (ovum) I can state that fertilisation is when the nucleus of a sperm and egg cell fuse to form a zygote I can state that fertilisation occurs in the oviduct of the female reproductive system I can state that the embryo develops in the uterus within an amniotic sac which has fluid to protect it from knocks and bumps

3 I can state that the embryo gains its food and oxygen from its mother via an organ called the placenta I can state that the embryo gets rid of carbon dioxide and other wastes via the placenta I can briefly describe the development of an embryo from a fertilised egg (zygote) to an embryo to a foetus I can name various external agents that may pose a risk to developing embryos and can describe effects that they can have. Make sure you have ticked off these learning outcomes by the end of the topic. Use the checklist when you are revising for a test or the S1 exam. Ask your teacher if you re unsure about any of the learning outcomes.

4 Activity 1 what s the common factor???? Collect a set of picture cards from your teacher. Every card has something in common. In your groups, try to make links between the pictures. Maybe start with small groups first and then try to decide one thing that all of the cards have in common. Write your ideas in the space below Microscope needed to see cells Plants, dog, human, micro-organisms all living organisms that are made up of cells Red blood cells type of cell Set of instructions each cell contains a set of instructions for the functioning of the cell Robert Hooke and Cork the discovery of cells Now watch a short video clip that introduces some interesting facts and images about cells. They really are amazing! Write down three things that you are excited to learn about in this topic. Various options here:

5 Cells and the microscope Every living organism on earth is made up of tiny building blocks called cells. A cell is the basic unit of life. Cells make up every organ in our body! Some organisms are made of only one cell; the human body on the other hand is made of around 10 trillion cells!!!! But what do they look like and what do they do? Use the word bank below to complete the following diagram which shows how living organisms are organised Cells tissue organ system system cells tissue organ

6 Activity 2 the structure of living cells There are two main basic types of cells animal cells and plant cells. Each cell is made up of structures that help the cell to do its job. Look at the labelled diagram on the left of an animal cell. A plant cell contains all of these structures too label them on the diagram on the right and then use page 94 of your textbook to label the three other structures. Show clearly which cell is animal and plant. Cell membrane Chloroplast Cytoplasm cytoplasm Nucleus nucleus Cell membrane Cell wall Vacuole animal cell plant cell Activity 3 using the microscope Living cells are so tiny that we need a microscope to see them. Your teacher will show you an animation which shows just how small a cell actually is!!

7 Give some examples of the cells you seen in this animation. You will be learning much more about these cells in this topic. A microscope is a very expensive piece of equipment. Your teacher will show you how to use this properly and there are instructions below be careful!! Use the microscope to look at the prepared slides. Draw a quick sketch of each in the boxes below. 1. Ensure you can see the light source by looking through the eyepiece. 2. Ensure the objective lens is at the lowest magnification 3. Lower the stage as far as the focusing handle will go 4. Place the microscope slide on the stage using metal clips. 5. Look through the eyepiece & carefully turn the focusing handle until the slide is in focus. 6. Move the revolving turret to the next power and use fine focusing knob if necessary

8 Homework 1 Use the wordbank on the left to label the diagram of the microscope Eyepiece Mirror Objective lens Focus knob Focusing knob Eyepiece Objective lens Stage Stage Mirror/ light source Each part of a cell has an important job. Use page 94 of your textbook to complete the table below Part of Cell Function Found in animal cell? Found in plant Cell? nucleus Controls the cell yes yes cytoplasm Site of chemical reaction yes yes vacuole Contains cell sap no yes Cell wall Cell membrane chloroplasts Provides support to the cell Allows substances to move in and out of the cell Site of photosynthesis no yes no yes yes yes

9 Activity 4 starter task As a group, use laminated cards to label the large diagram of plant and animal cells. Compare your answers with another group and check them against your completed diagrams on page 5. Activity 6 preparing animal and plant cell slides Earlier in the topic you looked at some animal and plant cells under the microscope. Before we can look at cells under the microscope they need to be put onto a glass slide and then have to be stained with a chemical so that we can see the structures of the cell clearly Today you are going to learn how to make your own slides Your teacher will show you how to prepare some slides of animal and plant cells. Follow the instructions below work in pairs to do one each. Draw what you see in the boxes below. Label any of the important parts we learned about in the last activity clearly. To prepare cheek cell slides 1. Move the cotton wool bud over the inside of the mouth and along the lower side of your gum. 2. Smear the cotton bud over a small area of the microscope slide. 3. Place the used cotton bud immediately in the disinfectant provided. 4. Place 1 drops of the stain methylene blue onto the smear and cover with a cover slip. Do this over the sink using a staining rack Hint - Take care not to add too much stain as this will affect your results. 5. Look at your sample under the microscope 6. The cytoplasm will be stained blue and the nucleus should be stained dark blue. 7. After the cells have been observed, immerse the slide and cover slip in a beaker of disinfectant. 8. Draw what you can see through the microscope. Label the cell membrane, nucleus, and cytoplasm.

10 To prepare onion cell slides 1. Collect a layer of onion from your teacher. 2. Place onion on slide and add a couple of drops of water 3. Place 1 drop of iodine stain onto the slide Did you know there are more bacterial cells than human cells in the human body!! 4. Gently lower the cover slip on top to avoid air bubbles (big black circles on slide). 5. Carefully blot off excess liquid with a paper towel. 6. Look through the microscope and draw what you see in the space below, labelling nucleus, cell membrane, cell wall, vacuole and cytoplasm. Cheek cell onion cell 1. Which part of the cell contains the genetic information? The nucleus 2. Why must cells be stained before we can look at them underneath the microscope? To see the structures more clearly (not to see the cells more clearly) 3. Name three parts of a plant cell not shared by an animal cell Chloroplast, cell wall, vacuole

11 Activity 7 starter task As a small group, use the laminated cards to match up each part of a cell with its function. Check your answer against your completed table in activity 4. Activity 8 specialised cells Not all cells look the same. Living organisms are made up of many different types of cells that do different jobs. Many cells have special features that allow them to do their jobs well. These are called specialised cells. Use the microscopes to look at some slides containing specialised cells Produce a table in the space below that shows the name of each type of cell and the special features that it has. Specialised cell Feature Function Red blood cells disc shaped/ Red pigment for carrying oxygen Palisade mesophyll lots of chloroplasts for photosynthesis Ciliated epithelium tiny hairs (cilia) help sweep mucus away Sperm tail for swimming Egg yolky cytoplasm food store Nerve cell long extension carrying nerve impulses Cartilage elastic and strong Rods and cones sensitive to light Xylem lignin to provide support Root hair large surface for absorbing water Bone flexibility and strength

12 Homework 2 specialised cell passports Your teacher will give you a type of specialised cell to research. Use the resources suggested below to complete the specialised cell passport. This will be used to create a class display so they must contain detailed and accurate information as well as look attractive! Ensure that you follow all of the criteria below. Use the space below to gather your information Information to include 1. Name what is the cell called 2. Address Which part of the body does the cell work in? Is it part of a tissue? 3. Occupation what job in the body does this cell do? How does it do this job? 4. Partner cells names of other cells that they work closely with to do their job 5. picture or diagram this should clearly show any special features that the cell has, e.g shape etc Suggested resources Page 96 of science textbook The information card provided Did you know cells commit suicide when damaged!

13 Activity 10 consolidation activity You are going to make a 3D model of a cell. Your teacher will provide you with the materials and instructions. You should ensure that all structures of the cell are represented and be prepared to talk about your model with others. Your model will be assessed by other in the class so make it good! Peer assessment use the assessment rubric provided by your teacher to provide a grade and comment to one other group on their model Did you know that there are over 210 different types of human cells! The following materials can be used to represent cell parts: cell wall Tupperware box cell membrane food bag cytoplasm wall paper paste/jelly inside food bag chloroplasts frozen peas inside jelly/wall paper paste nucleus- small inflated balloon, bouncy balls inside jelly/wall paper paste vacuole small food bag filled with water inside wall paper paste/jelly Activity 11 consolidation activity Some cards are repeats of cell passport activity. Others are additional Collect a set of cards showing images and words relating to specialised cells. With your group, match up the words with the images to show: i) the name of the cell ii) the location of the cell iii) the special features each cell has to help it to do it s job. Pick 5 of these cells and produce a table to show the above information for each 13

14 Homework 3 My journey to the centre of the cell.. Just imagine if we could shrink ourselves down to be the same size as cells and we could look inside! Imagine you can do this and you are visiting a plant cell. Produce a story that documents your travels to the centre of the cell. Your story must name all parts of the plant cell that you have learned about. The way that you do this is up to you but try to be as imaginative and creative as you can. You may wish to consider the following: - what did you see/feel/touch/smell - use lots of adjectives (descriptive words) - could you see the parts doing their jobs? If so what were they doing? - try to imagine what it would be like to be actually in the cell Your story should be written or typed on no more than 1 piece of A4 paper and should have some images or pictures. 14

15 Cells and reproduction Did you know the three things that pregnant woman dream most about is frogs, worms and potted plants! Twig on Glow science vids very good here Reproduction is the process of making new offspring and is very important as it enables a species to survive. Male and female mammals have reproductive organs that work together as part of the reproductive system. You will have already learned about these in primary. Activity 12 the male and female reproductive system Demo - Work together as a class to try and label all of the parts of the male and female reproductive system on the interactive game. Now use the wordbank to label each part of the male and female reproductive systems and complete the tables below Gland Scrotum testi Sperm tube Scrotum Sperm tube gland Testi Penis Penis ovary Uterus/womb Uterus oviduct Oviduct Ovary Vagina cervix Cervix Vagina 15

16 Name of Structure Testes/ testi Sperm duct/ sperm tube Scrotum gland Penis Function Production of sperm Carries the sperm to the penis. A bag of skin which holds the testis provides sperm with the energy to move Carries the sperm out of the body Name of Structure Vagina oviduct Uterus/ womb cervix ovary Function Where penis deposits sperm and is the birth canal Site of fertilisation Where fertilised egg implants and develops Sits at the neck of the womb Production and storage of eggs 16

17 Activity 13 sex cells The ovary and testes are responsible for producing special sex cells that fuse together during sexual reproduction. These were two of the specialised cells you learned about in activity 8. Read the following passage carefully. As you are doing this highlight any key ideas or words (including the one s you don t know the name of). Then read the passage again and complete the diagrams and table that follows The sex cells are the cells that fuse together during sexual reproduction to form a new cell that will eventually form a new organism. The female sex cell is called the egg or ovum and is produced in the ovary. These round cells are the largest in the human body. They have a cell membrane, cytoplasm and nucleus. The cytoplasm contains a rich food store which provides an energy source for the new organism that will eventually grow. They are visible to the naked eye, being about the size of the dot at the end of this sentence. Once the female sex glands have matured during puberty, they normally release not more than one egg per month. Even so, in the course of a woman's life their total number may very well reach more than 400. The male sex cell is called sperm. Sperm cells are produced in the male testes. They are the smallest cells in the human body. While they are invisible to the naked eye, they can be seen and studied under the microscope. An individual sperm cell has a certain vague resemblance to a very skinny tadpole, Its total length is about mm (1/600th of an inch). The head, which is only of the length of the sperm, has a nucleus containing all of the genetic information. Sperm have tails which allow them to swim. The sperm can move ahead at the rate of 2 cm per minute under favourable conditions. This movement is essential since the sperm has to reach the egg deep inside the woman's body. Once the male sex organs have matured during puberty, they produce millions of sperm cells every day. 17

18 _animal cell _plant cell Cell membrane tail cytoplasm nucleus Sperm egg Name of organ in Testes Ovary which produced size 0.042mm Size of a full stop Special features Tail allows them to swim 2cm per minute Largest cell in the human body Homework 4 read pages 100 and questions 1-4 Did you know most babies are born with blue eyes and can change after birth when the pigment melanin darkens on exposure to light! 18

19 Activity 14 starter task As a group use the laminated cards to label the large diagram of male and female reproductive system. Compare your answers with another group and check them against your completed diagrams on page 16. Activity 15 - life s greatest miracle In order to produce a new organism, the nucleus of the male and female sex cells must fuse. In many animals, including humans, these cells come together during sexual intercourse when a man inserts his penis into a woman s vagina. Watch the video that shows the processes involved in sexual reproduction and then answer the questions that follow. 1. Where does a male deposit his sperm during sexual intercourse? vagina 2. Name the process whereby the nucleus of the sperm and egg fuse? Why do you think it is so important that the nuclei fuse? Fertilisation- this is where the genetic information is stored the DNA of the baby will consist of copies of half of the mothers DNA and half of the fathers. This information will provide the information for all of the baby s characteristics. 4. Where in the female reproductive tract does this process happen? Oviduct/fallopian tube 5. What name is given to a fertilised egg cell? zygote Did you know a foetus acquires fingerprints at 3 months! 6. Where does the fertilised egg cell implant to continue its development? Uterus wall 7. Describe what happens to the fertilised egg as it continues its development. Divides to produce increasing number of cells (ensure that pupils do not think that cells increase in size) 8. Describe how the female reproductive system prepares itself for a pregnancy each month 9. How is the foetus protected from knocks and bumps during its development? The amniotic sac and fluid 19

20 10. Name the structure that allows the foetus and mother to exchange substances The placenta Activity 16 life s greatest miracle mythbuster Collect a set of cards from your teacher containing various statements about sexual intercourse and pregnancy. Read through each statement in your group deciding whether you agree, disagree or are unsure about each. Create three piles and then compare your thoughts with another group. Activity 17 Askit basket Hopefully today s lesson has answered some of your questions about sexual intercourse and reproduction. If you have any other questions or worries then write your question on the slip of paper provided and pop it in the basket. This is anonymous so you do not have to add your name. Activity 18 - consolidation Collect a set of cards containing the beginning and ends of sentences about sexual reproduction, fertilisation and embryonic development. Match them up to make full sentences. Once your teacher has checked them write the full sentences in the space below. 20

21 Activity 19 the developing embryo Did you know a baby s teeth start to grow about 6 months before it is born! It is incredible to think that we all developed from one single cell! The development of an embryo from a fertilised egg cell to a baby is a complicated and amazing process! Watch the video showing the development of an embryo throughout pregnancy In your small group use the information from the video and the website below to produce an information card about the stage of foetal development you have been assigned. Ensure that you follow the criteria below. This will be used to create a whole class timeline of development! Criteria for information card Your card should contain/show the following information: 1. the period of development in days or weeks 2. the length/size/weight of the foetus at this stage 3. the main developments that take place during this time any organs formed,any distinguishable features etc 4. an image showing what the foetus looks like at this time 5. any other interesting/relevant information that you find Useful websites suggested weeks 0-8 weeks 9-16 weeks weeks 25 - birth 21

22 Homework 5 1. Rewrite the following terms into the correct sequence to describe the increasing number of cells: New born baby, egg, embryo, zygote, foetus 2. Write a sentence to explain the function of each of the following: a) the placenta b) amniotic fluid c) umbilical cord d) oviduct e) uterus 3. How long in total does a foetus take to fully develop? 4. At 2 weeks of development an embryo is made of 1024 cells. At 4 weeks of development it is made of 4096 cells. What % of the total cells after 4 weeks was developed at 2 weeks? 5. What was the average weekly increase in the number of cells during the first 4 weeks of development? 6. What is the simple whole number ratio of the number of cells at 2 weeks to the number at 4 weeks? 7. Label the following diagram using the wordbank provided, Uterus wall, Embryo, Amniotic Fluid, Umbilical cord 22

23 Activity 20 starter activity - timeline of life Collect a card showing a stage of development. Work together with your classmates to put yourself in the correct order to show a timeline of life Activity 21 factors that affect the development of the embryo As you have seen the development of the human embryo is a complicated process! Embryo s are very vulnerable during these stages and their development can be seriously affected by many external agents such as chemicals, pathogens and drugs. You will work in your group to produce a public health campaign in the form of a TV advert to warn expectant mothers of these risks. In your groups assign the following roles: 1. camera operator 2. researcher 3. presenter 4. facilitator Criteria Your TV campaign will: 1. Describe the dangers/risks associated with your external agent on a developing embryo/foetus 2. Give examples of abnormalities that can be caused by this agent 3. Describe the steps that should be taken by an expectant mother to avoid the dangers posed by this external agent. 23

24 Extension 1 Look at the following table and draw a bar graph showing how the lining of the uterus changes during the menstrual cycle DAY THICKNESS OF UTERUS LINING mm 2 2.1mm 4 1.3mm 6 1.0mm 8 1.0mm mm mm mm mm mm mm mm mm mm Colour the bars for days 0 to 6 in red to show menstruation and 14 to 16 yellow to show ovulation. The remaining bars should be coloured blue. Write menstruation and ovulation on the graph in the correct places Sperm can live for 3 days. An egg can live for 2 days. A woman ovulates between day 12 and day 14. Her fertile period is any time when, as a result of sex, she could conceive. Can you work out when a woman might be fertile? Put arrows on your graph to show when a woman is fertile. Say how you came to your decision Test your understanding of the cycle by answering the following questions: a) What is the period of bleeding called? b) What is the biological name for the uterus lining? c) What is the release of an egg called? d) What is the period when fertilisation could take place called? e) How is day 1 of the cycle marked? 24

25 Extension 2 The instructions on how to use a microscope have been intentionally messed up. Sort the following statements into the correct order in your jotter. A) Lower stage as far as focusing handle will go B) Place microscope slide on stage using metal clips. C) Ensure objective lens is at the lowest magnification D) Ensure the light source by looking through the eyepiece. E) Look through the eyepiece & carefully turn focusing handle until slide is in focus. 25

26 Glossary Word Cell Microscope Magnification Tissue Stain Cell wall Cell membrane Vacuole Cytoplasm Nucleus Chloroplast Specialised cell Reproduction Fertilisation Testi Ovary Scrotum Penis Sperm tube Vagina Cervix Definition Basic unit of life Piece of apparatus used to magnify cells and small structures The process of enlarging an object in appearance not in physical size A group of cells that work together to perform a specific function Chemical applied to cells in order to see their structures more clearly Provides support to a plant cell Allows substances to move in and out of a cell Found in plant cell only. Contains cell sap and is involved in the movement of water in and out of cells Site of chemical reactions Controls all cellular processes contains the genetic information Contains chlorophyll site of photosynthesis Cell that has a specific function and has special structural and functional features that allow the cell to perform its function Process of producing offspring Fusion of the nuclei of a sperm and egg cell Part of male reproductive system that produces sperm Part of female reproductive system that produces eggs Sac-like structure that contains the testes Inserted into the female reproductive tract during intercourse. Releases sperm during ejaculation Carries sperm from the testes to the penis Place where penis is inserted during sexual intercourse. Opening to the womb through which baby is delivered. 26