Biology Meiosis and Fertilization Concepts

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Questions and Answers

What is a major advantage of internal fertilisation over external fertilisation?

It increases the genetic variation within a population.

It results in a higher number of gametes produced.

It allows sperm to have a direct route to the egg cell. (correct)

It is less energy-consuming in seeking mating partners.

Which process describes asexual reproduction in plants involving the production of genetically identical offspring?

Sexual reproduction

Genetic recombination

Mitosis (correct)

Fusion of gametes

What is one disadvantage of internal fertilisation?

Lower genetic variation due to selectivity in mating. (correct)

Increased offspring production compared to external fertilisation.

Less energy required for mating.

Higher chance of fertilisation per gamete.

Which of the following is NOT a type of vegetative propagation in plants?

Mitosis Signup and view all the answers

What type of underground stem helps in storing food and gives rise to new plants?

Tuber Signup and view all the answers

What is the main characteristic that distinguishes asexual reproduction from sexual reproduction?

Fusion of gametes. Signup and view all the answers

Which reproductive strategy typically results in a higher success rate of fertilisation?

Internal fertilisation Signup and view all the answers

Which of the following is a key disadvantage of asexual reproduction?

Limited offspring genetic diversity. Signup and view all the answers

What does the process of random segregation lead to in gametes?

Increased genetic variation Signup and view all the answers

During which phase do sister chromatids separate in a haploid cell?

Anaphase II Signup and view all the answers

What occurs during Telophase II?

Uncoiling of coiled chromatids Signup and view all the answers

What role does helicase play during DNA replication?

Unwinds the DNA helix Signup and view all the answers

What is the result of cytokinesis II?

Four haploid gametes Signup and view all the answers

How many alleles does each gamete inherit for a given gene?

One Signup and view all the answers

What happens to the microtubules during Telophase II?

They begin to break down Signup and view all the answers

Which nitrogenous bases are involved in the occurrence of hydrogen bonds during DNA replication?

Adenine, Thymine, Guanine, and Cytosine Signup and view all the answers

What are suckers in plant reproduction?

New shoots that arise from roots or underground stems. Signup and view all the answers

In which organism does fragmentation occur as a form of reproduction?

Starfish. Signup and view all the answers

What is the primary method by which strawberry plants propagate?

Runners. Signup and view all the answers

What distinguishes sexual reproduction from asexual reproduction in plants?

Sexual reproduction involves gametes from two parents. Signup and view all the answers

What type of reproduction can result in genetically identical offspring from a single parent plant?

Self pollination. Signup and view all the answers

During sexual reproduction in mammals, what is the primary process that creates gametes?

Meiosis. Signup and view all the answers

What type of cells are produced through meiosis?

Non-somatic (sex) cells. Signup and view all the answers

What is a key feature of bulbs in plant reproduction?

They provide nutrients for the plant's survival. Signup and view all the answers

Why does crossing over not occur during mitosis?

Homologous chromosomes are not aligned side-by-side along the equator. Signup and view all the answers

What type of chromatids undergo crossing over to create new allele combinations?

Non-sister chromatids of a homologous pair. Signup and view all the answers

What does it imply when both sister chromatids carry the same allele at a locus?

They are exact copies of each other. Signup and view all the answers

What is the consequence of crossing over occurring between sister chromatids?

No new genetic variation occurs. Signup and view all the answers

What does a capital letter represent in terms of alleles?

A dominant allele. Signup and view all the answers

How does the distance between genes on a chromosome relate to crossing over?

Increased distance increases the chance of crossing over. Signup and view all the answers

What is true about homologous pairs of chromosomes?

They can carry different alleles for the same gene. Signup and view all the answers

What represents a recessive allele in this genetic context?

Lowercase letter Signup and view all the answers

What is the primary structure of a protein primarily determined by?

Amino acid sequence of the polypeptide Signup and view all the answers

Which type of bonding is primarily involved in the formation of a protein's secondary structure?

Hydrogen bonds Signup and view all the answers

What is the significance of the tertiary structure of a protein?

It provides the protein's functional three-dimensional shape. Signup and view all the answers

What happens when B cells are activated in response to a foreign substance?

They release proteins called antibodies. Signup and view all the answers

How do ionic bonds contribute to protein structure?

They enhance tolerance to variations in pH and temperature. Signup and view all the answers

Which of the following statements about protein structure is true?

Quaternary structure is related to polypeptide chains interacting together. Signup and view all the answers

Why is the order of amino acids in a polypeptide chain critical?

It dictates the way chemical bonds form between amino acids. Signup and view all the answers

What does the secondary structure of proteins primarily involve?

Coiling into helixes and forming sheets Signup and view all the answers

Study Notes

Random Segregation

During Anaphase II, sister chromatids separate randomly to opposite poles of the haploid cell.
This random separation creates four gametes, each with a unique combination of chromosomes.
It is impossible to predict which chromatid will end up in each gamete.
Segregation increases the genetic variation of gametes and offspring.

Telophase II

The coiled chromatids begin to uncoil.
Cytokinesis II occurs, resulting in four haploid gametes.
Each gamete inherits one allele of every gene.
A new nuclear membrane forms around the two chromatids in each gamete.
The microtubules break down.
One centrosome goes to each daughter cell.
Depending on the organism's gender, the gametes are either sperm or egg cells.

Internal Fertilization

Internal fertilization has a higher fertilization success rate per gamete compared to external fertilization.
Internal fertilization provides a direct route for sperm to reach the egg inside the female's body.
This reduces the impact of external environmental factors on sperm cells.
Disadvantages of internal fertilization:
- Less mating partner options, leading to lower genetic variation.
- More energy is required to find a mating partner and perform mating.
- Fewer gametes are produced, leading to a lower overall amount of offspring.

Asexual Reproduction

Asexual reproduction occurs when one parent produces offspring through cell division.
The offspring are genetically identical clones of the parent.
No fusion of gametes occurs during asexual reproduction.
Asexual reproduction in plants is called vegetative propagation.

Vegetative Propagation

Vegetative propagation occurs when a parent plant produces a genetically identical offspring.
Examples include tubers, stolons, rhizomes, suckers, fragmentation, and runners.
Tubers are swollen underground stems that store food and can produce new plants.
Stolons are long stems that grow along the surface and produce new roots and leaves.
Rhizomes are underground stems that give rise to new shoots and roots.
Suckers are new shoots that arise from roots or underground stems.
Fragmentation occurs when a part of the parent organism separates and develops into a new individual.
Runners are stems that extend from a plant and produce new roots at nodes, forming new genetically identical plants.
Bulbs are underground buds that can develop into new plants.

Sexual Reproduction

Sexual reproduction involves the fusion of gametes from two parents.
The offspring inherits genetic material from both parents and is not genetically identical to either.
Gametes are sex cells such as sperm and egg cells in humans.
The process of producing gametes is called meiosis.

Self-Pollination

Self-pollination occurs when a plant produces both pollen and ovules, which then combine to produce offspring.
Self-pollination can result in either genetically identical or different offspring, depending on whether the plant is homozygous or heterozygous for the genes.
Self-pollination is considered a type of sexual reproduction because it involves the fusion of gametes.

Continuity of Species

During reproduction, genetic information (DNA) is copied and passed on to offspring.
The offspring's genetic material is stored in their cells' nuclei.

Protein Structure

Proteins play a crucial role in supporting the survival of organisms.
Protein shape and function are closely related.
There are four levels of protein structure: primary, secondary, tertiary, and quaternary.
Primary structure: The sequence of amino acids in a polypeptide chain.
Secondary structure: The way a polypeptide chain coils into helixes due to hydrogen bonds.
Tertiary structure: The further coiling of polypeptide chains into a three-dimensional shape, involving additional types of bonds like ionic bonds.
Quaternary structure: The interaction of multiple polypeptide chains to form a functional protein.

Crossing Over

Crossing over is a process that occurs during meiosis I.
It involves the exchange of genetic material between non-sister chromatids of homologous chromosomes.
Crossing over creates new combinations of alleles, contributing to genetic variation.
Crossing over does not occur in mitosis because homologous chromosomes do not align side-by-side during the process.

Sister Chromatids

Sister chromatids are two identical copies of a single chromosome.
They carry the same alleles for all genes.
Crossing over can occur between sister chromatids, but it does not lead to new allele combinations.
The longer the distance between genes along a chromosome, the greater the chance of crossing over.

Alleles

Alleles are alternate forms of a gene.
Alleles are located at specific positions on chromosomes called loci.
By convention, a capital letter represents a dominant allele, and a lowercase letter represents a recessive allele.
Homologous chromosomes carry alleles for the same genes at corresponding loci.

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Description

This quiz covers key concepts of meiosis, focusing on random segregation during Anaphase II, the events of Telophase II, and the significance of internal fertilization. Understanding these processes is crucial for recognizing how genetic variation occurs and how fertilization strategies impact reproductive success.