B15.1
Asexual reproduction
Asexual reproduction
Which of the following are disadvantages of asexual reproduction in plants?
1. produces many individuals rapidly
2. lack of variation
3. individuals will have more resistance to disease
A 1 only
B 2 and 3
C 2 only
D 1 and 3
C, 2 only
Which one of the following is a process involved in sexual reproduction?
A Meiosis in gamete production
B Reproduction in bacteria
C Runners on a strawberry plant
D Mitosis in gamete production
A, Meiosis in gamete production
_____ is the transfer of pollen from the anther to the stigma. It can occur by insects or the _____.
1. Pollination
2. Wind
What is the term for different versions of the same gene?
Alleles
How many daughter cells are produced in meiosis?
4
Give 2 advantages and 2 disadvantages of asexual reproduction.
Advantages: Fast, No partner needed, All beneficial traits are cloned.
Disadvantages: No variation so diseases are easily transmitted, Fast reproductions uses up resources too fast, Offspring can't adapt to changes in the big environment.
46 chromosomes
Arranged in pairs
Give the 3 environmental conditions that are needed to allow the germination of seeds.
Water, oxygen and a suitable temperature.
Describe the relationship between DNA, genes, and chromosomes.
Chromosomes are made of DNA molecules, which contains genetic information in the form of genes.
What is the difference between haploid and diploid cells?
Haploid cells have half the number of chromosomes (e.g., gametes with 23 chromosomes in humans), while diploid cells have two full sets of chromosomes (e.g., body cells with 46 chromosomes in humans).
Name an energy-consuming process that occurs immediately after zygote formation.
Cell division
Nucleus of a zygote is _____ and the nuclei of gametes are _____.
Diploid
Haploid
The diagram below shows the structure of a sperm cell.
https://docs.google.com/document/d/17LE4I9GUyNb5aDyniPu3R5BFnTopsvhajQnqhhmBNsw/edit?tab=t.0
Once a sperm cell meets an egg cell, enzymes are released to help the sperm cell to break through the jelly-like coating of the egg cell. Where in the sperm cell are these enzymes stored?
Acrosome
Explain the differences between mitosis and meiosis in terms of chromosome number and genetic variation.
Mitosis produces two genetically identical daughter cells, each with the same number of chromosomes as the parent (diploid). Meiosis produces four genetically unique gametes, each with half the chromosome number (haploid), increasing genetic variation.
Explain the importance of mitosis in multicellular organisms.
Mitosis is essential for growth, repair, and asexual reproduction in multicellular organisms. It ensures that each new cell has an identical set of chromosomes, maintaining genetic stability. During growth, mitosis allows the organism to increase in size, and during repair, it replaces damaged or dead cells.
Think about the number of chromosomes in human gametes and other human cells.
Which of the following options is correct?
A 23 chromosomes in gametes, 46 chromosomes in zygote, haploid number is 46, diploid number is 92
B 23 chromosomes in gametes, 46 chromosomes in zygote, haploid number is 46, diploid number is 46
C 23 chromosomes in gametes, 46 chromosomes in zygote, haploid number is 23, diploid number is 46
D 46 chromosomes in gametes, 46 chromosomes in zygote, haploid number is 23, diploid number is 46
C, 23 chromosomes in gametes, 46 chromosomes in zygote, haploid number is 23, diploid number is 46
Describe two differences between sexual and asexual reproduction.
Sexual reproduction involves the fusion of gametes (sperm and egg), whereas asexual reproduction does not involve gametes.
Sexual reproduction results in genetic variation among offspring, whereas asexual reproduction produces genetically identical offspring (clones).
Sexual reproduction typically requires two parents, whereas asexual reproduction requires only one parent.
Sexual reproduction is generally slower and requires more energy, while asexual reproduction is faster and more energy-efficient.
Which feature(s) of an egg cell ensures the correct number of chromosomes after fertilisation?
1 and 2
Describe Mitosis in terms of how it changes the number of chromosomes and what it leads to.
Describe meiosis as reduction division in which the chromosome number is halved from diploid to haploid resulting in genetically diferent cells.
Describe four characteristics of asexual reproduction. (Extra marks for 5th)
Involves only one parent (1)
Offspring are genetically identical (clones) to the parent (1)
No gametes or fertilization involved (1)
Usually occurs through processes such as binary fission, budding, or vegetative propagation (1)
Rapid reproduction, allowing for fast population growth (1)
Describe the process of fertilization in humans and explain why sexual reproduction leads to genetic variation.
Fertilization occurs when a male sperm cell fuses with a female egg cell.
The sperm travels through the female reproductive system to meet the egg in the oviduct.
The nuclei of the sperm and egg fuse to form a zygote.
Sexual reproduction involves the combination of genetic material from two parents.
This results in genetic variation due to the mixing of alleles, leading to offspring with unique genetic traits.
Identify all components of a pollinated flower in this image.
https://docs.google.com/document/d/1cZJElEubfKSTxf7mNVueI5radVGI5v0XWvppaPIlOXE/edit?tab=t.0
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