Grade 12 Life Sciences: DNA and Meiosis

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Questions and Answers

Who is identified as the biological father of the child?

Male 1

Male 4

Male 3 (correct)

Male 2

What is one precaution that should be taken to avoid contamination when handling DNA samples?

Use unwashed equipment from previous experiments

Store samples in non-sterile containers

Mark the samples clearly to avoid mix-ups (correct)

Keep samples exposed to the air

Which two individuals are identified as identical twins from the DNA profiles?

A and B

B and D

E and D

C and F (correct)

Who are identified as the parents of person B based on the DNA profiles?

A and E Signup and view all the answers

What are the potential concerns related to collecting DNA from every citizen to create a DNA profile database?

It raises ethical issues and privacy concerns Signup and view all the answers

What is the product formed during transcription?

mRNA Signup and view all the answers

How many templates are used in the process of DNA replication?

2 Signup and view all the answers

Which molecule carries amino acids during protein synthesis?

tRNA Signup and view all the answers

What does a codon in an mRNA molecule represent?

A specific amino acid Signup and view all the answers

What occurs at the ribosomes during protein synthesis?

Translation Signup and view all the answers

How many codons are typically shown in a sequence of mRNA?

3 Signup and view all the answers

What is the relationship between amino acids and codons?

1 amino acid is coded by 1 codon Signup and view all the answers

Which of the following correctly represents a sequence of bases during DNA synthesis?

A-T and C-G Signup and view all the answers

What occurs during Prophase I of meiosis that contributes to genetic variation?

Homologous chromosomes pair and undergo crossing over. Signup and view all the answers

What is the result of crossing over during meiosis?

Genetic variation is introduced among the resulting cells. Signup and view all the answers

At which stage of meiosis do homologous chromosomes separate and move to opposite poles?

Anaphase I Signup and view all the answers

What is true about the daughter cells formed after Telophase I?

They are haploid and genetically varied. Signup and view all the answers

During which phase do spindle fibers attach to the chromosomes in meiosis?

Metaphase I Signup and view all the answers

Which statement accurately describes the chromosome composition after the first meiotic division?

Each daughter cell receives one chromosome from each homologous pair. Signup and view all the answers

What happens during Metaphase I of meiosis that enhances genetic diversity?

Independent assortment occurs. Signup and view all the answers

What is the primary function of meiosis in organisms?

To create genetic variation in gametes. Signup and view all the answers

What is a biological importance of DNA replication?

It ensures the preservation of genetic information. Signup and view all the answers

How does a mutation that alters a DNA codon affect protein synthesis?

It can lead to the production of a different protein. Signup and view all the answers

Which statement describes the outcome of a single nucleotide change in DNA?

It may result in a different amino acid being included. Signup and view all the answers

What describes a mutation involving adenine being changed to cytosine?

A point mutation that can affect protein structure. Signup and view all the answers

In the event of a codon change from AUA to AUU, what is the expected consequence?

The resulting protein may differ due to the amino acid change. Signup and view all the answers

What is an example of a result from DNA replication mistakes?

Gene mutations that can affect the phenotype. Signup and view all the answers

What defines the nature of a mutation that leads to a significant change in protein function?

It can result in a single amino acid substitution. Signup and view all the answers

Which mutation type can introduce a completely different protein into an organism?

A frameshift mutation shifting the reading frame. Signup and view all the answers

What type of chromosome is structure B considered to be?

Replicated chromosome Signup and view all the answers

During which phase of meiosis does non-disjunction occur?

Anaphase I Signup and view all the answers

How many chromosomes are present in a normal gamete formed after meiosis?

23 Signup and view all the answers

What type of mutation involves a change in the structure and number of chromosomes?

Chromosomal mutation Signup and view all the answers

What is the primary distinction between structure B and structure C?

Structure B is made of two chromatids, while structure C is made of one chromatid. Signup and view all the answers

What process is depicted at location A in the diagram of meiosis?

Non-disjunction Signup and view all the answers

What separates during Anaphase I of meiosis?

Homologous chromosomes Signup and view all the answers

How many pairs of chromosomes are typically present in a normal human sperm cell?

23 Signup and view all the answers

Which part of a chromosome attaches to the spindle fibres during cell division?

Centromere Signup and view all the answers

Which part of the chromosome directly represents a gene?

Locus Signup and view all the answers

What is the phase of meiosis represented in a typical early diagram during prophase?

Prophase I Signup and view all the answers

Identify the phase of meiosis represented in a diagram showing alignment at the cell's equator.

Metaphase II Signup and view all the answers

Which part of the cell contains the DNA during meiosis?

Nucleus Signup and view all the answers

What forms the spindle fibres during meiosis?

Centriole Signup and view all the answers

What is the name of the process during which genetic material is exchanged between homologous chromosomes?

Crossing over Signup and view all the answers

Study Notes

Introduction

This self-study guide is for Grade 12 Life Sciences students.
It addresses the topics of DNA, the code of life, and meiosis.
The guide aims to address learning gaps created by the COVID-19 pandemic.
The guide focuses on essential topics, skills, and concepts in Grade 12 to strengthen mastery of subject knowledge.
It emphasizes independent learning and mastering core cross-cutting concepts.

How to use this self-study guide

Five booklets cover all Grade 12 topics.
Booklet 1: DNA: Code of Life and Meiosis
Booklet 2: Reproduction in Vertebrates, Human reproduction, Endocrine System and Homeostasis
Booklet 3: Genetics and Inheritance
Booklet 4: Responding to the Environment: Humans and Plants
Booklet 5: Evolution: Natural Selection and Human evolution
Use this guide with the Life Sciences Mind the Gap Study Guide.
Study the content from the DBE Grade 12 Textbook, DBE Exam Guideline 2021, and Mind the Gap.
Master the relevant concepts and content.
Focus on exam techniques and tips for approaching specific question types.
Practice questions and answers included

DNA: The Code of Life

Prior knowledge: Plant and Animal cells, proteins, nucleic acids, location of DNA and chromosomes.
Mind map on DNA - Code of life: Covers location of RNA, structure of RNA, function of RNA, translation, transcription, protein synthesis, and DNA related aspects
Links to prior knowledge/Background knowledge (Examples: cell structure, organelles, functions of organelles, etc.)
Differentiate between related terminologies (Examples: chromatin vs. chromatids, DNA vs. RNA, genes vs. alleles, etc.)
DNA Replication: Exam techniques, tips, and notes, practice questions, solutions
DNA profiling: Exam techniques, tips, and notes, practice questions, solutions
Protein Synthesis: Exam techniques, tips, and notes, practice questions, solutions
Genetic coding: Exam techniques, tips, and notes, practice questions, solutions
The effect of mutation: Exam notes, practice questions, and solutions regarding how mutations affect DNA sequence and protein structure

Meiosis

Mind map on Meiosis
Links to prior knowledge/Background knowledge
Differentiate between related terminologies
Meiosis process: Exam techniques, tips, and notes, practice questions, solutions
Practical questions on Meiosis
Typical exam questions, solutions to questions

DNA Replication - Exam Tips

Detailed step-by-step process of DNA replication
Explanation of errors occurring during DNA replication (mutations).

DNA Profiling- Exam Tips

Explanation of DNA profiling
How to interpret DNA profiles (bands/bars)
Practical application in paternity testing and forensic investigations
Precautions to be taken when handling DNA samples.

Protein Synthesis - Exam Tips

Describes the process of transcription and translation
Explains the role of mRNA, tRNA, and rRNA in protein synthesis

Genetic Coding - Exam Tips

Definition of genetic coding
Importance of proteins.
Details on triplets (codons).

The effect of mutation on Protein Structure

Explanations on mutations affecting DNA and the changes that occur in protein sequences
Diagrams and scenarios showing how mutations affect the formation of a protein.

Practice Questions and Solutions

Varied practice questions (multiple choice, short answer, diagrams, etc.)
Solutions for DNA replication, transcription, genetic coding, and protein synthesis.
Solutions for DNA profiling.
Practice questions regarding meiosis
Solutions for process of meiosis questions

References

List of sources used for the information

Acknowledgement

Acknowledge the people/organizations involved in creating the guide

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Description

This self-study guide is designed for Grade 12 Life Sciences students focusing on essential topics like DNA, the code of life, and meiosis. It aims to bridge learning gaps exacerbated by the COVID-19 pandemic and supports independent mastery of critical concepts. Students will benefit from thorough coverage across five booklets, reinforcing their subject knowledge and skills.