7BR – ReproductionName:

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1. What is sexual reproduction? The production of new living organisms from two different sexes.

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2. What is a gamete? A sex cell (sperm in males and ova/egg cells in females)3. What are the two human gametes? Sperm (males), ovum (female)4. What is fertilisation? When two gametes meet5. What is the function of the sperm cell? Swim to the ovum and fertilise it6. What are the two key adaptations of the

sperm cell? Tail, lots of mitochondria7. Why do sperm have tails? Help them swim8. Why do sperm have lots of mitochondria Release energy for swimming9. What is the function of the ovum? Be fertilised and provide nutrients for the embryo to

grow10. What are the two key adaptations of an

ovum? Very big, changeable cell membrane11. Why is an ovum so big? Contain lots of nutrients for the embryo12. Why do ova have changeable cell

membrane? To stop more than one sperm entering it13. What is a zygote? The fertilised ova14. What is DNA? A chemical that contains instructions for all life

processes15. Where is DNA found? In the nucleus16. What are chromosomes? Strands of DNA bunched up together17. How many chromosomes do most human

cells have? 46 (23 pairs)18. How many chromosomes do gametes

have? 2319. What is variation? Differences between living things (of the same species)20. Where do humans get their first

chromosomes from?Half from the mother, half from the father (23 from each)

21. Why are siblings different if they are from the same parents?

They don’t receive the same 23 chromosomes from each parent

22. What is an embryo? An organism in the early stages of development, up to 8 weeks.

23. What is a foetus? An unborn baby, after 8 weeks from conception.24. What is the function of the ovaries? To produce ovum (and secrete hormones)25. What is the function of the oviducts? Transport the ova from the ovary to the uterus 26. What is the function of the uterus? To nourish and protect the developing embryo/foetus 27. What is the function of the uterus lining? Provide an initial site for the embryo to develop28. Describe the structure of the cervix A ring of muscle at the lower end of the uterus. 29. What is the function of the cervix? It keeps the foetus in place while the woman is

pregnant.30. What is the structure of the vagina? A muscular tube that leads from the cervix to the

outside of the woman's body. 31. What is the function of the vagina? Serves as a passage for the penis and menstrual flow

from the uterus.32. What is the function of the testes? To produce sperm (and secrete hormones)33. What is the function of the glands? Produce fluids that protect sperm cells

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34. What is the function of the sperm ducts? To transport sperm from the testes to the penis35. What is the function of the penis? To pass urine and sperm (semen)36. What is the function of the urethra? Carries urine and sperm (semen) out of the body37. What is the umbilical cord? A tube going from the placenta to a developing foetus38. What is the placenta? An organ that connects the mother to the umbilical cord39. What are the functions of the umbilical

cord and placenta?To pass oxygen and nutrients to the foetus and waste to the mother

40. How many days is a menstrual cycle? Average of 28 days41. What happens at the start of the

menstrual cycle? Menstruation42. What is menstruation? When the uterus lining starts to break down43. How long does menstruation last? Average of five days44. What happens after menstruation? Uterus lining starts to grow and thicken45. Why does the uterus lining grow and

thicken?To provide somewhere for the zygote to develop into an embryo

46. What is ovulation? When the ovaries release an ovum47. When does ovulation occur? Around day 14 of the menstrual cycle48. What happens if fertilisation does not

occur?The uterus lining starts to break down and the cycle continues

49. In plants, what are the male sex cells? Pollen50. In plants, what are the female sex cells? Ova51. What are the anthers? Where pollen is produced (male)52. Where are plant ova produced? Ovules53. What is the stigma? The part of the flower where pollen is collected (female)54. What is pollination? When pollen moves from an anther to a stigma55. What are the two main types of

pollination? Insect pollination and wind pollination 56. Why do some plants have brightly

coloured flowers? To attract insects57. What happens after pollination? Fertilisation and seed growth58. What is seed dispersal? How seeds move away from the parent plant59. How can seed dispersal occur? By wind, eaten by animals, stuck to the outside of

animals

Lesson 1: sexual reproduction

I am learning about gametes so I can explain how fertilisation occurs

Recap primer questions:1. What is a cell?2. What is the function of the:

a. Nucleus b. Mitochondria c. Cell membrane4

3. What is a specialised cell?4. Name three specialised human cells5. What is binary fission?6. How many cells do we start with in binary fission?7. How many cells do we finish with in binary fission?8. Are the cells produced in binary fission similar to the cells we start with in binary fission?In the cells unit we learnt about binary fission. This is how a cell replicates itself and becomes two identical daughter cells. There is no difference between the daughters, and they are the same as the parent. This is a type of reproduction: a process of making new cells.In this unit we will look at a different type of reproduction: sexual reproduction. In this type of reproduction we don’t make identical cells, but we make cells which have variation: they are different. There are two parents involved in sexual reproduction; the male and the female. The male and the female both release special cells called gametes. When these cells meet, fertilisation occurs, and new offspring can develop. Comprehension questions:

9. What is produced in binary fission?10. What is reproduction?11. What is a gamete?12. What is variation?13. Complete the sentence to compare binary fission with sexual reproduction:

In binary fission…..but in sexual reproduction…

In humans, the gametes are specialised cells called ova and sperm cells. Ova are produced by the female, sperm are produced by the male:Cell Diagram Function Two key

adaptationsPurpose of the adaptation

Ovum (egg cell – plural is ova)

Be fertilised and provide nutrients for the embryo to grow Very big,

changeable cytoplasm

Big to hold lots of nutrients for the embryo, cytoplasm changes once one sperm has passed through it. This stops other sperm entering.

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Sperm Swim to the ovum and fertilise it

Tail, lots of mitochondria

Tail for swimming, mitochondria to release energy to swim

14. From memory, explain why sperm have tails15. What are the two key adaptations of the ovum?16. Why do egg cells need nutrients?17. Egg cells need mitochondria, but not as many as sperm cells. Explain why. 18. At any one time, the male could produce millions of sperm. Explain why only one fertilises the

ovum.19. Egg cells are 0.15mm in size. How big to they appear when viewed under a microscope with x40

magnification?20. A student looks at a sperm cell under a microscope with 100x magnification and it appears to be

5mm in length. How big is the sperm cell actually?21. Use look, cover, write, check, to begin memorising the table above. Lesson 2: Introducing variation

I am learning about DNA and genetic information so I can explain how gametes introduce variationThe nucleus of a cell holds DNA. This is a chemical that gives instructions to the cell what it should be doing and how it should be acting. The DNA is made of long strands of atoms, and different parts of the strands hold instructions to do different things. Some parts of the strand might tell a cell to make a protein that helps with digestion, other strands might tell a cell whether it should be a nerve cell or a muscle cell. Everything that happens in your body depends on the instructions help in the DNA. The DNA is bunched up into bigger structures called chromosomes. The majority of your cells have 46 chromosomes and they are arranged in pairs (so 23 pairs of chromosomes). In each pair, one chromosome is from your mother and one is from your father. Gametes contain only 23 chromosomes, so both the ovum and the sperm only have half the chromosomes needed. When the two cells meet and fertilise each other, their chromosomes match up, meaning that there is now 46 chromosomes in a joined-together cell. This cell is called a zygote. 22. What is DNA?23. Where is DNA found?24. When DNA is all bunched up, it forms a structure called a __________25. Put the below in order of size from biggest to smallest:

nucleus chromosome cell DNA26. How do you know red blood cells do not have DNA?27. How many chromosomes do most of your cells have?28. How many chromosomes do sex cells have?29. What is the difference between a gamete and the other cells in your body?30. What is a zygote?31. Challenge: In binary fission, the parent cell duplicates (creates a copy of) its DNA. Explain why it

needs to do this to ensure the daughter cells are genetically identical.Half of your chromosomes are from your mother, and half are from your father. Because people have different chromosomes, we all have different “instructions” for our bodies. This is why different humans

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can look and behave so differently – we have different chromosomes. This is called variation: where individuals within a species (like humans) can be different to each other.When you get your chromosomes from your parents, there is no telling in advance which 23 chromosomes you will get. It is random which 23 happen to go into this particular ovum and this particular sperm. This is why siblings can be different to each other – because the chromosomes they get are different, even though the parents are the same. 32. How many chromosomes do normal cells have?33. How many chromosomes do gametes have?34. How many chromosomes do zygotes have?35. Where are a person’s chromosomes from?36. Why do most people look similar to their parents?37. What is variation?38. A student writes:

Siblings get all their DNA from the same place so it doesn’t make sense that there are differences between themExplain why the student is wrong.

39. Complete the sentence stems:Non-siblings are different because…Siblings are different because…Non-siblings are different but…Siblings are different but…

40. From memory, give two key adaptations of sperm and ova and explain why they have these adaptations.

41. Go back to your notes and perfect your answer with a purple pen. Once the zygote has been formed, it starts to grow. For the first 8 weeks, we call it an embryo. After that we call it a foetus. After a total of about 40 weeks (so a further 32 weeks), the mother gives birth to a baby. 42. The sentences below summarise all the information above. Put them into order in your exercise

book.A zygote is formedThis is called fertilisationThe foetus develops until it is bornThe embryo becomes a foetusA sperm cell meets an ovumThe zygote grows into an embryo

Lesson 3: reproductive organs

I am learning about the reproductive organ systems in males and females to understand how sexual reproduction occurs

Males and females have a number of reproductive organs. Each of these has a different function and plays a different part in sexual reproduction. Your teacher will show you how to label the diagrams below. We will only be focussing on a few key organs and functions.

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What is the function of the ovaries? To produce ovum (and secrete hormones)What is the function of the oviducts? Transport the ova from the ovary to the uterus What is the function of the uterus? To nourish and protect the developing embryo/foetus What is the function of the uterus lining?

Provide an initial site for the embryo to develop

Describe the structure of the cervix A ring of muscle at the lower end of the uterus. What is the function of the cervix? It keeps the foetus in place while the woman is pregnant.What is the structure of the vagina? A muscular tube that leads from the cervix to the outside of the

woman's body. What is the function of the vagina? Serves as a passage for the penis and menstrual flow from the

uterus.What is the function of the testes? To produce sperm (and secrete hormones)What is the function of the glands? Produce fluids that protect sperm cells What is the function of the sperm ducts?

To transport sperm from the testes to the penis

What is the function of the penis? To pass urine and sperm (semen)What is the function of the urethra? Carries urine and sperm (semen) out of the body

During sexual intercourse, the male inserts his penis into the female’s vagina. Sperm are ejaculated (pushed out) from his testes, through the sperm ducts, through the urethra and into the female’s body. They swim (and are pushed) into the oviducts, where an ovum may be waiting (we will learn about this later). If fertilisation occurs, the zygote moves into the uterus and onto the uterus lining where it develops into an embryo. 43. Label the diagram with as many labels

as you can: 44. Where does fertilisation take place?45. When the sperm meets the ovum, what is

formed?46. During ejaculation, millions of sperm

are released. Why does only one fertilise the ovum?

47. Where is the ovum produced?48. In general, what substances go out of

the penis?49. Below are a series of words and phrases. You need to write a sentence that contains all the words or

phrases. They can be in any order. The first one has been done for you:a. Sperm cells/urethra/in order to

sperm cells travel through the urethra in order to get to the ovumb. Ova/oviductc. Gamete/fertilise/afterwardsd. Sperm/swim/function/thereforee. Gamete/zygote/chromosomesf. Uterus lining/embryo/resulting ing. Cervix/foetus/thereforeh. Ova/nutrients/becausei. Sperm cells/testes/initially j. Zygote/oviduct/finallyk. Sperm/ova/prior to

Lesson 4: foetal development

I am learning about how the foetus develops in the uterus

If fertilisation occurs, the zygote develops on the uterus lining into an embryo, then a foetus. Two temporary organs start to form which will connect the foetus to the mother. This is necessary

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because the foetus needs to take oxygen and nutrients in, and pass waste products back. The placenta and umbilical cord work together to allow this to happen. 50. Which substances go from the mother to the foetus?51. Which substances go from the foetus to the mother?52. How long does it take for an embryo to turn into a foetus?53. How long does it take after that for the foetus to develop?54. Where does the embryo first develop?55. Inside the placenta are structures with a very large surface area. These structures move substances

from the mother to the umbilical cord. Explain fully why they have a large surface area. 56. What occurs in fertilisation? Include the words in your answer: sperm, ovum, zygote, chromosome,

gamete, oviduct57. List the organs which sperm pass through in order. 58. Some women have weak cervixes. Explain why doctors might use a stich in order to strengthen it

while the woman is pregnant. Lesson 5: the menstrual cycle

I am learning about the stages of the menstrual cycle and its role in sexual reproduction

An important part of puberty for females is the beginning of their monthly cycle. This is known as the menstrual cycle. The menstrual cycle involves the preparation of the uterus lining so that it can receive a fertilised egg. If an egg is fertilised, it can implant itself in the prepared uterus lining. If it is not fertilized, the lining of the uterus breaks down and is lost from the body. This is called menstruation or a period. Below is key information about the menstrual cycle:How many days is a menstrual cycle? Average of 28 daysWhat happens at the start of the menstrual cycle?

Menstruation

What is menstruation? When the uterus lining starts to break downHow long does menstruation last? Average of five daysWhat happens after menstruation? Uterus lining starts to grow and thickenWhy does the uterus lining grow and thicken?

To provide somewhere for the zygote to develop into an embryo

What is ovulation? When the ovaries release an ovumWhen does ovulation occur? Around day 14 of the menstrual cycleWhat happens if fertilisation does not occur? The uterus lining starts to break down and the cycle

continues

59. Describe what happens on day 1 and day 14 of the menstrual cycle60. Explain why the uterus lining thickens61. Where does the ovum go after ovulation?62. An ovum can survive for about 36 hours after it is released. If ovulation takes place on day 14, until

when can fertilisation occur?63. Sperm can survive in the uterus for close to three days. Explain why fertilisation can occur even if

sex occurred before ovulation. 64. If a female ovulates and releases two ova, twins could be born. Explain how this occurs referring to

sperm and fertilisation. 65. These twins would be non-identical. Explain why, referring to chromosomes and both parents. 66. What is the difference between a gamete and a zygote?67. From memory, list as many reproductive organs as you can.68. For each one, state if it is female or male.69. For each one, state its function.

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Lesson 6: Plant reproduction

I am learning about reproductive organs in plants so I can explain how plants undergo sexual reproduction

Plants also have male and female sex organs and male and female gametes. Generally, the male sex cells are found in pollen, and female sex cells are also ova, but they are held and produced in an ovule. For many plants, the organs are part of the flowers. Your teacher will label the diagram with you.

Pollen is produced by the anthers. If pollen lands on a stigma, then fertilisation can occur by genetic material moving down the flower to the ovule. 70. Name one male plant sex organ and one female plant sex organ71. What are the sex cells in plants? 72. Spinach is a plant. Its cells have 24 chromosomes in 12 pairs. How many chromosomes do its sex

cells have?73. Why can new spinach plants from the same parents be different to each other?74. In the winter, many plants do not have flowers. Explain why sexual reproduction cannot take place

for these plants in the winter.Lesson 7: pollination

I am learning about the different types of pollination so I can explain why plants are structured the way they are

Pollen is produced at the anthers and needs to get to a stigma. This process is called pollination, and happens in one of two ways:Insect pollination: this is where insects carry pollen from plant to plantWind pollination: this is where the pollen is carried by wind. Pollinating insects include flies, bees and butterflies. They are attracted to flowers by bright colours and land on the flower. The flowers can produce a substance called nectar, which the insects use for food (some also use pollen for food). Whilst they are on the flower, pollen gets stuck to them. They fly away to another flower for more nectar, and when they land some of the pollen drops off and lands on the stigma. 75. Explain why some flowers have bright petals76. Bees have lots of little hairs all over them. Explain why this makes them excellent pollinators.77. Why is nectar necessary for plants to undergo insect pollination?

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78. The smallest pollen grains are around 0.0006cm. What magnification would be required to view them with an image size of 2.1mm?

79. Hummingbirds are pollinators. Many hummingbirds have a mass of just a couple of grams. Why are heavier birds not good pollinators?

In wind pollination, the pollen is blown off the anthers by wind. The anthers tend to be exposed in plants which rely on wind pollination. Many people are allergic to pollen and when there is a lot of pollen in the air can get a runny nose and sore eyes. This is called hay fever. 80. Why is hay fever worse on windy days?81. Why do plants which rely on wind pollination not normally have flowers?82. A student wants to know how the wind affects the pollen count. They have five fans which have

different speeds and five plants. They can also measure the pollen count with a special device. They set the experiment up like this in five different rooms:

a. What is the independent variable?b. What is the dependent variable?c. Name as many controlled variables as you can

83. The student’s results look like this:Fan speed Pollen

count1 3.22 6.13 9.34 11.85 14.9

With your teacher, draw a graph to show these results.84. Describe the pattern in the results85. A person has very bad hay fever and plants lots of plants in their home. All the plants have very

bright flowers. Explain why these plants do not affect their hay fever that much.86. Some plants give off smells which are similar to ones given off by female insects. Why do you think

they do this?Lesson 8: seed dispersal

I am learning about how plants produce and disperse their seeds

After a flower has been pollinated, fertilisation occurs. The newly formed zygote grows into a seed, which contains all the DNA necessary for a new plant to grow. The parent plant does not want that plant to grow near it as it may compete for water, light and nutrients. Therefore, plants disperse their seeds far away from them. This can happen in a number of different ways:By wind: the seeds are adapted to be carried very far by the wind.On the outside of animals: these seeds tend to have spikes on the outside of them which stick to animal fur. The animals carry them as they move and then they fall off.

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Detector

Eaten by animals: these seeds are edible or have edible coatings (like fruit) and are eaten by animals (including us). When the animal excretes, the seed can grow where it lands.

87. Below are two different seeds:

a. How do you think goosegrass seeds are dispersed?b. How do you think goat’s beard seeds are dispersed? Explain your answer.c. Using a ruler, measure the size of the goosegrass seed. it has been magnified to four

times its size. Calculate its actual size. d. Goat’s beard has many flowers that give off a scent. How do you think it is pollinated?

Explain your answer. Lesson 9: continuous and discontinuous variation

I am learning about how we use different methods to display continuous and discontinuous data

Members of the same species are all similar but do show differences. Humans are a species, and each of us looks different – eye colour, height and shoe size are all examples of the differences between individuals. The scientific term for these differences is “variation”.

Variation is group into two types: Continuous variation and discontinuous variation.

Continuous variation is for things like height, weight or hand span. They are characteristics that change gradually over a range of values, and the value could fall anywhere within a range. Continuous variation is usually caused by both inheritance (parents) and your environment (things that happen around you).

A graph of continuous variation often has this classic shape known as a bell curve. For height, for example, there are lots of people with a similar height, but few people who are very small or very tall:

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Discontinuous variation is for things like blood group, sex (male or female) or ability to roll your tongue. These variations take one of only a limited number of possible values. Discontinuous variation is usually only caused by inheritance.

88. Describe the differences between continuous and discontinuous variation. 89. Below is a table showing the heights of a group of people. Your teacher will show you how we plot it

as a distribution graph. Height category (cm) Number of people in categoryLess than 130 1130 to less than 135 5135 to less than 140 13140 to less than 145 26145 to less than 150 31150 to less than 155 34155 to less than 160 32160 to less than 165 25165 to less than 170 13170 to less than 175 5175 or more 1

90. Suggest why the peoples’ heights were grouped into categories instead of using each individual’s actual height.

91. What causes continuous variation?92. The same group of people above had their blood group recorded. Draw a bar graph of the data

table below.Blood group Number of people in categoryA 78B 7AB 19O 82

93. What causes discontinuous variation?94. For each of the following, identify if it is continuous or discontinuous variation.

a) How deep into the ground the roots of a cactus go.b) Peppered moths can either be light in colour, or dark in colour. c) Snap dragon petals can be red, white or pink. d) How much milk a cow can produce in litres.e) Hand span (this is a measure of the distance between the tip of someone’s little finger and

their thumb, when their hand is stretched out).f) Length of giraffe necks.g) The colour of a jelly baby.

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