Cell Structure And DNA
Aperçu
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.
Objectifs
- 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
Carte mentale
Ce theme est schematise pour montrer comment les idees se relient.
Ouvrez la carte mentale dans l'application
Cartes memoire
Entrainement rapide sur les faits evalues dans ce theme.
Entrainez-vous sur ces cartes dans l'application
Note de cours
Fiche complete disponible sur l'application Green Bridge
Installez l'application Green Bridge CBT sur votre telephone ou votre ordinateur pour acceder a toute la bibliotheque IGCSE : sujets d'examen, baremes, cartes mentales, fiches memo et lecons audio.
Évaluation de la leçon
Félicitations, vous avez terminé la leçon sur Cell Structure And DNA. Maintenant que vous avez exploré le concepts et idées clés, il est temps de mettre vos connaissances à lépreuve. Cette section propose une variété de pratiques des questions conçues pour renforcer votre compréhension et vous aider à évaluer votre compréhension de la matière.
Vous rencontrerez un mélange de types de questions, y compris des questions à choix multiple, des questions à réponse courte et des questions de rédaction. Chaque question est soigneusement conçue pour évaluer différents aspects de vos connaissances et de vos compétences en pensée critique.
Utilisez cette section d'évaluation comme une occasion de renforcer votre compréhension du sujet et d'identifier les domaines où vous pourriez avoir besoin d'étudier davantage. Ne soyez pas découragé par les défis que vous rencontrez ; considérez-les plutôt comme des opportunités de croissance et d'amélioration.
- 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
Travaillez ces questions dans l'application
Travaillez ces questions dans l'application
Livres recommandés
Pour aller plus loin, ressources libres
-
Section de manuel
Protein Synthesis
Explain how the genetic code stored within DNA determines the protein that will form
"Anatomy and Physiology: Protein Synthesis" by OpenStax, OpenStax, Rice University, licensed under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Source: https://openstax.org/books/anatomy-and-physiology/pages/3-4-protein-synthesis. Access for free at https://openstax.org/books/anatomy-and-physiology/pages/1-introduction
-
Section de manuel
Nucleic Acids
Describe the structure of nucleic acids and define the two types of nucleic acids
"Biology: Nucleic Acids" by OpenStax, OpenStax, Rice University, licensed under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Source: https://openstax.org/books/biology/pages/3-5-nucleic-acids. Access for free at https://openstax.org/books/biology/pages/1-introduction
Publiées par d'autres organisations sous licence libre, créditées comme elles le demandent. Les liens ouvrent leurs sites.
Pratiquez des questions blanches
Vous voulez vous entraîner sur des questions blanches sur Cell Structure And DNA ? Téléchargez lapplication Green Bridge CBT pour accéder à des questions blanches et à des évaluations complètes sur ce sujet.
Téléchargez l'application sur Google Play.
Tout ce dont vous avez besoin pour exceller au JAMB, WAEC et NECO.
