Cell Structure And DNA
Overview
Every decision your body makes, from building a new skin cell after a graze to fighting off a cold, starts with an instruction written in a molecule barely two nanometres wide. That molecule is DNA, and it is coiled inside the nucleus of almost every one of your cells, carrying the complete set of instructions needed to build and run a human being.
In this lesson you will learn the structures a light microscope and an electron microscope reveal inside a human cell, discover how DNA's double helix lets it copy itself with astonishing accuracy, and follow the two-step journey, transcription then translation, that turns a gene into a working protein.
Objectives
- Recognise cell structures as seen with a light microscope and electron microscope (TEM images only), including nucleus, chromosomes, cell membrane, mitochondria, endoplasmic reticulum and ribosomes
- Describe the functions of the cell structures: nucleus, chromosomes, cell membrane, mitochondria, endoplasmic reticulum, ribosomes
- Describe the structure of a DNA molecule as two strands coiled to form a double helix, containing nucleotides, strands linked by complementary bases, complementary bases linked by hydrogen bonds
- Describe DNA replication as the separation of DNA strands and the formation of a new strand by complementary base pairing of nucleotides, including the role of DNA polymerase
- Understand that a gene is a length of DNA containing a sequence of bases that code for a specific protein
- Know that RNA is a second type of nucleic acid that is single stranded, contains ribose, contains uracil and is used to take information from DNA in the nucleus to the ribosomes for the synthesis of proteins
- Understand that a DNA mutation involves a change in the sequence of bases that could lead to a change in the amino acid sequence and phenotype of an individual
- Describe protein synthesis as transcription (the formation of mRNA in the nucleus), the transfer of mRNA to ribosomes in the cytoplasm, translation of the genetic code by tRNA from mRNA codons, and the formation of a polypeptide chain using amino acids
Lesson Note
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Lesson Evaluation
Congratulations on completing the lesson on Cell Structure And DNA. Now that youve explored the key concepts and ideas, its time to put your knowledge to the test. This section offers a variety of practice questions designed to reinforce your understanding and help you gauge your grasp of the material.
You will encounter a mix of question types, including multiple-choice questions, short answer questions, and essay questions. Each question is thoughtfully crafted to assess different aspects of your knowledge and critical thinking skills.
Use this evaluation section as an opportunity to reinforce your understanding of the topic and to identify any areas where you may need additional study. Don't be discouraged by any challenges you encounter; instead, view them as opportunities for growth and improvement.
- Which structure can only be seen in detail using an electron microscope, not a light microscope? A) Nucleus B) Cell membrane outline C) Internal structure of a mitochondrion D) Cytoplasm Answer: C
- In a DNA molecule, adenine always pairs with: A) Guanine B) Cytosine C) Thymine D) Uracil Answer: C
- Which enzyme joins new nucleotides together during DNA replication? A) RNA polymerase B) DNA polymerase C) DNA ligase D) Amylase Answer: B
- Where in the cell does transcription take place? A) Ribosome B) Mitochondrion C) Nucleus D) Cell membrane Answer: C
- Which of these is a difference between RNA and DNA? A) RNA contains uracil instead of thymine B) RNA is double stranded and DNA is single stranded C) RNA contains deoxyribose and DNA contains ribose D) RNA is found only in mitochondria Answer: A
Available on the Green Bridge App
Download the Green Bridge CBT app on your phone or computer to access full lesson notes, practice questions, and more.
Available on the Green Bridge App
Download the Green Bridge CBT app on your phone or computer to access full lesson notes, practice questions, and more.
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