Biology - Genetics

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Questions and Answers

What is the main purpose of meiosis?

Growth and repair

Cellular maintenance

Asexual reproduction

Sexual reproduction (correct)

Crossing over occurs during meiosis II.

False

What is the structure of DNA?

double helix

In meiosis I, homologous pairs of chromosomes are separated to form two _____ cells.

haploid Signup and view all the answers

Match the following DNA base pairs with their complementary pairs:

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

What is the significance of crossing over during meiosis?

Crossing over introduces genetic variation by exchanging DNA between homologous chromosomes. Signup and view all the answers

Compare the number of cells produced in mitosis and meiosis.

Mitosis produces 2 identical diploid cells, while meiosis produces 4 genetically different haploid cells. Signup and view all the answers

How do the roles of mitosis and meiosis differ in organisms?

Mitosis is used for growth and repair in somatic cells, while meiosis is used to produce gametes in germ cells for sexual reproduction. Signup and view all the answers

Explain how DNA structure supports its function in genetic coding.

The double helix structure of DNA allows for stable storage of genetic information and proper pairing of base pairs for accurate replication. Signup and view all the answers

What happens to sister chromatids during meiosis II?

In meiosis II, sister chromatids are pulled apart by spindle fibres, resulting in the formation of four haploid daughter cells. Signup and view all the answers

What is the purpose of adding pineapple juice in the DNA extraction process?

It breaks down proteins to visualize the DNA. Signup and view all the answers

Ethanol is added to the solution to help visualize DNA by causing it to precipitate.

True Signup and view all the answers

What should you observe after leaving the solution for 10 minutes during DNA extraction?

A white precipitate at the top of the tube Signup and view all the answers

The DNA extraction solution is combined with chopped kiwi and left to sit for _____ minutes.

20 Signup and view all the answers

Match the following steps in DNA extraction with their descriptions:

Add ethanol = DNA precipitates making it visible Add pineapple juice = Proteins are broken down for clearer DNA visibility Filter the solution = Separates solid plant material from liquid Leave for 10 minutes = Observe the formation of a precipitate Signup and view all the answers

What role does the DNA extraction solution play in the extraction process?

It helps to break down cell membranes and release DNA from the kiwi cells. Signup and view all the answers

List one advantage and one disadvantage of sexual reproduction.

An advantage is that the method produces genetically diverse DNA, while a disadvantage is that it requires more time. Signup and view all the answers

Why is it important to leave the mixture for 20 minutes after combining the kiwi and extraction solution?

Leaving it for 20 minutes allows for sufficient breakdown of cell components to release the DNA. Signup and view all the answers

What observation indicates that DNA has been successfully extracted after adding ethanol?

A white precipitate should appear at the top of the tube, indicating the presence of DNA. Signup and view all the answers

How does the enzyme bromelain in pineapple juice aid in the DNA extraction process?

Bromelain breaks down proteins, which helps to clarify and visualize the extracted DNA. Signup and view all the answers

Which type of allele is only expressed in the absence of a dominant allele?

Recessive Allele Signup and view all the answers

Homozygous individuals inherit different alleles from each parent.

False Signup and view all the answers

What is the genetic makeup of an organism called?

Genotype Signup and view all the answers

Cystic fibrosis is mainly caused by a __________ allele.

recessive Signup and view all the answers

Match the following terms with their definitions:

Allele = An alternative form of a gene Phenotype = The observable characteristics of an organism Mutation = A change in the DNA sequence Genome = All genes in an organism Signup and view all the answers

What was the primary goal of the Human Genome Project?

To determine the sequence of the human genome Signup and view all the answers

Mutagens are factors that can lead to mutations.

True Signup and view all the answers

What chromosome pair determines the sex of a human?

XX or XY Signup and view all the answers

The genetic diagram that shows how traits are inherited is called a __________.

Punnett Square Signup and view all the answers

What might be the effect of a beneficial mutation?

It may result in an evolutionary advantage. Signup and view all the answers

Match the following terms related to genes with their definitions:

Allele = One of a number of alternative forms of a gene Phenotype = The features expressed as a result of the alleles present Mutation = A change in the order of bases in DNA Genome = All genes in your body Signup and view all the answers

Match the following types of alleles with their characteristics:

Dominant Allele = Always expressed in an individual Recessive Allele = Expressed only in the absence of the dominant allele Homozygous = Inherits identical alleles for a feature Heterozygous = Inherits two different alleles for a feature Signup and view all the answers

Match the following types of mutations with their effects:

No Effect = Neutral changes Harmful = Protein no longer functions normally Beneficial = Provides an evolutionary advantage Mutagen = Factor that can lead to mutations Signup and view all the answers

Match the following terms with their related concepts in heredity:

Gamete = Sex cell Punnett Square = Diagram showing how traits are inherited Fertilization = Sperm fuses with egg Carrier = An individual who carries a recessive allele without expressing it Signup and view all the answers

Match the following components of the human genome with their descriptions:

Human Genome Project = Determined the sequence of the human genome Base Pairs = Units of DNA consisting of two complementary nucleotides Chromosomes = Thread-like structures containing genes Alleles = Alternative forms of a gene Signup and view all the answers

Match the following genetic terms with their definitions:

Genotype = The alleles present in an organism Chromosome = Structure made of protein and DNA Dominance = Phenomenon where one allele masks the expression of another Recessiveness = Condition requiring two copies of an allele for expression Signup and view all the answers

Match the following human traits with their genetic principles:

Cystic Fibrosis = Inherited disorder caused by a recessive allele Sex Determination = Determined by sex chromosomes (XX or XY) Carrier Status = 50% chance of passing on a recessive disorder Inheritance Patterns = Ways traits are passed from parents to offspring Signup and view all the answers

Match the following aspects of DNA replication with their potential outcomes:

Mutation = Incorrect base sequence leading to changes in traits Natural Selection = Survival of beneficial mutations Genetic Variation = Results from combinations of alleles DNA Repair = Mechanism that corrects mistakes in base pairing Signup and view all the answers

Match the following organisms with their adaptations:

Polar Bear = White fur for camouflage Camel = Fat stored in hump for heat loss Cactus = No leaves to reduce water loss Signup and view all the answers

Match the following types of variation with their examples:

Continuous variation = Weight Discontinuous variation = Blood group Signup and view all the answers

Match the following types of variation with their descriptions:

Inherited variation = Combination of parents' genes Environmental variation = Effects of upbringing Continuous variation = Range of values varies Discontinuous variation = Specific values only Signup and view all the answers

Match the following adaptation descriptions with the corresponding organism:

Camel = Large feet to spread weight on soft sand Cactus = Spines to deter herbivores Polar Bear = Thick layer of blubber for insulation Signup and view all the answers

Match the following descriptions with their respective categories of variation:

Environmental variation = Affected by temperature and moisture Inherited variation = Passed down through genes Continuous variation = Controlled by environmental factors Discontinuous variation = Examples include blood group Signup and view all the answers

How do polar bears' physical adaptations support their survival in cold environments?

Polar bears have small ears to reduce heat loss, a thick layer of blubber for insulation, and white fur for camouflage. Signup and view all the answers

What is the difference between continuous and discontinuous variation, and provide one example of each?

Continuous variation allows features to vary over a range, such as height, while discontinuous variation has distinct categories, like blood group. Signup and view all the answers

Define inherited variation and environmental variation and give an example of each.

Inherited variation results from genetic combinations from parents, such as eye color, while environmental variation is influenced by external conditions, like plant height due to sunlight. Signup and view all the answers

Describe one adaptation of a camel that helps it survive in sandy environments.

Camels have sandy-colored fur for camouflage and large feet to spread their weight on soft sand. Signup and view all the answers

How does the lack of leaves in a cactus contribute to its survival in arid regions?

The absence of leaves reduces water loss, and spines help deter herbivores from eating them. Signup and view all the answers

Study Notes

Meiosis

Meiosis begins when each chromosome replicates, making a copy of itself.
In the first division (meiosis I), chromosomes align in homologous pairs.
Crossing over takes place between homologous pairs, creating new combinations of genetic material. This generates genetic variation in the resulting daughter cells.
Homologous pairs are pulled apart by spindle fibres, resulting in two haploid cells.
In the second division (meiosis II), sister chromatids line up again at the equator in each of the two cells.
Sister chromatids are pulled apart by spindle fibres.
The result is 4 haploid daughter cells that are genetically unique.
Meiosis is for sexual reproduction, producing gametes, rather than cell growth or repair. This process is essential for producing genetic diversity in offspring.

DNA Structure

DNA is a long molecule found in each cell.
A section of DNA is called a gene.
DNA codes for a specific protein.
DNA has a double helix shape.
Two strands of DNA, called polynucleotides, are made of nucleotides.
The strands are held together by weak hydrogen bonds, forming base pairs: adenine with thymine and guanine with cytosine.
The four bases are adenine, thymine, guanine, and cytosine. These bases pair in a specific way to ensure the correct sequence in the DNA molecule.
These bases are joined together by phosphate molecules and deoxyribose sugar, forming the structure of the DNA molecule. The specific sequence of these base pairs determines the genetic code.

Comparing Mitosis and Meiosis

Mitosis produces identical cells for growth and repair. Meiosis produces gametes (sex cells) for sexual reproduction.
Mitosis produces 2 diploid cells, while meiosis produces 4 haploid cells.
Mitosis produces cells with the same number of chromosomes as the original, while meiosis produces cells with half the number.
Mitosis produces genetically identical cells, while meiosis produces genetically different cells, leading to variation. This variation is crucial for the adaptation and survival of species.
Mitosis is for growth and repair, whereas meiosis is for sexual reproduction. Understanding their differences is key in understanding how organisms develop and reproduce.

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Description

Test your knowledge on the processes of meiosis and the structure of DNA. This quiz covers key concepts such as chromosome replication, crossing over, and the double helix structure of DNA. Challenge yourself to remember the complexities of genetics and cellular division.