Learn and test your biological vocabulary using these 11.4 Sexual reproduction flashcards
Summary list for 11.4 Sexual reproduction
Gametogenesis
- Similarities in spermatogenesis and oogenesis include mitosis, cell growth, two divisions of meiosis and differentiation.
- Students need to be able to annotate diagrams of seminiferous tubule and ovary to showing these details.
- Differences between the processes in spermatogenesis and oogenesis are the different numbers of gametes produced and the different amounts of cytoplasm in these gametes.
- Annotation of diagrams of mature sperm and egg to indicate functions.
Fertilization
- Fertilization in animals can be internal or external.
- Fertilization involves the acrosome reaction, fusion of the plasma membrane of the egg and sperm and the cortical reaction (mechanisms that prevent polyspermy).
Early growth of the embryo
- Implantation of the blastocyst in the endometrium is essential for the continuation of pregnancy.
- HCG stimulates the ovary to secrete progesterone during early pregnancy.
- The placenta facilitates the exchange of materials between the mother and fetus.
- Estrogen and progesterone are secreted by the placenta once it has formed.
- Birth is mediated by positive feedback involving estrogen and oxytocin.
Skills & applications
- To make comparisons of gestation periods and animal size & to find the place of the average human (38-week) pregnancy on a graph showing the correlation between animal size and the development of the young at birth in mammals.
- To annotate diagrams of stages of gametogenesis in seminiferous tubule and an ovary.
- Ability to annotate diagrams with the function of the parts of mature sperm and egg.
Mindmaps
These diagram summaries cover the main sections of topic 11.4 about sexual reproduction.
Study them and draw your own list or concept map from memory.
Sexual reproduction
Understanding the structure of mature sperm cells and the placenta are both important steps in understanding their function in this topic. Many students learn the names or all the parts of a sperm.
This question helps to practise explaining the functions of these parts.
Answer this question on a piece of paper, then check your answer against the model answer below.
Describe the structure and function of a sperm cell. [5]
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Click the + icon to see a model answer.
Multiple choice questions
This is a self marking quiz containing questions covering the topic outlined above.
Try the questions to check your understanding.
START QUIZ!
Which statement describes similarities between spermatogenesis and oogenesis?
Similarities in spermatogenesis and oogenesis include mitosis, cell growth, two divisions of meiosis and differentiation.
In spermatogenesis which cells divide by mitosis?
Spermatogenesis and oogenesis include mitosis, at the outer layer of germ cells in each seminal vesicle.
Students need to be able to annotate diagrams of seminiferous tubule to show these details.
The diagram below shows cells in a seminal vesicle of a testis.
Which of the labels shows a cell most likely to be in the process of differentiation?
Spermatogenesis and oogenesis includes differentiation of haploid cells into sperm cells.
Students need to be able to annotate diagrams of seminiferous tubule to show these details.
Which of the following correctly describes differences between spermatogenesis and oogenesis?
Differences between the processes in spermatogenesis and oogenesis are the different numbers of gametes produced and the different amounts of cytoplasm in these gametes. Oogenesis produces one large ovum and the polar bodies degenerate.
The diagram below shows mature spermatozoa.
Which correctly shows the functions of parts A, B and D? (C is not included in this question)
Annotation of diagrams of mature sperm should indicate their functions
A is the tail for movement
B is the midpiece which is full of mitochondria for respiration
C is the nucleus which contains the genetic material
D is the acrosome, contianing enzymes for penetration of the egg
Fertilization in many species of fish is different from mammals because the male sprays sperm onto eggs laid by the females in the water.
What is the name given to this type of fertilisation
Fertilization in animals can be internal or external depending on the place where the gametes meet.
Many species of fish use external fertilisation.
It is interesting to note (but not necessary for IB Biology) that in live-bearing fish, such as guppies and platys, males transfer packages of sperm to the female reproductive tract, using a modified anal fin, where they can be stored for more than a month.
The image shows a sperm about to fertilize an egg cell.
Several processes occur during the fertilisation of an egg and sperm cell.
In which order do the three processes given below occur.
Fertilization involves
- attraction of the sperm towards the egg
- binding of the sperm to the egg
- the acrosome reaction,
- fusion of the plasma membrane of the egg and sperm and
- the cortical reaction. (mechanisms that prevent polyspermy)
- fusion of the male and female nuclei
After fertilisation a fertilised egg divides and forms a hollow ball of cells called a blastocyst
Where in the human reproductive system could a blastocyst be found?
Implantation of the blastocyst in the endometrium is essential for the continuation of pregnancy.
Which features of the villi in the placenta help the exchange of materials between the mother and embryo?
The placenta facilitates the exchange of materials between the mother and fetus.
It is the mother's blood which surrounds the villi, and the large surface area of villi helps exchange of substances.
Which hormone is secreted by the placenta immediately following the implantation of the blastocyst?
hCG is produced as soon as implantation occurs. This is the hormone used in pregnancy testing.
Estrogen and progesterone are secreted a little later, by the placenta once it has formed.
The birth of a baby is an interesting example of feedback controlled by hormones.
It is a positive feedback process.
What is the hormone involved and what is it's role?
Birth is mediated by positive feedback involving estrogen and oxytocin.
Oxytocin causes contractions of the uterus wall which themselves promote an increase in the secretion of oxytocin.
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The graph below shows the body mass of a range of animals plotted against their mass at birth.
What is the general trend shown in the graph?
To make comparisons of gestation periods it can be assumed that babies grow a a similar rate, and birth size on the graph relates to a longer gestation.
This graph shows a surprisingly good correlation between animal size and the birth size, which could also relate to the more advanced development young at birth in larger mammals.
The graph below shows the gestation periods of a range of different animals plotted against their mass at birth.
Which of the points A to D on the graph is most likely to represent a human embryo?
You should be able to find the place of the average human (38-week) pregnancy on a graph showing the correlation between animal size and the development of the young at birth in mammals, or birth mass. Humans have a mass of between 50000g and 100000g, and babies are commonly about 3000g at birth. So humans a likely to be in the clusted below the letter B.
What is the function of the part labelled B in the mature sperm cell shown below?
Ability to annotate diagrams with the function of the parts of mature sperm and egg.
What mechanism prevents the entry of a second sperm cell after fertilization?
The cortical granules are released and prevent polyspermy during fertilization.
Everyone needs a bit of fun while they revise. Try this Carbon cycle card matching game.
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