Unit 4 - Genetic information, variation and relationships between organisms
Resumen
Summary - Unit 4 - Genetic information, variation and relationships between organisms
9 vistas 0 veces vendidas
Grado
Unit 4 - Genetic information, variation and relationships between organisms
Institución
AQA
This comprehensive set of A-Level Biology notes is meticulously crafted to provide students with essential information and streamlined content that reinforces understanding of key concepts
Unit 4 - Genetic information, variation and relationships between organisms
Todos documentos para esta materia (131)
Vendedor
Seguir
sanhiahussain
Vista previa del contenido
AQA A Level Biology
Topic 4 Genetic
information, variation
and relationships
between organisms
Model answer notes by @biologywitholivia
Topic Understand Memorise Practise
4.1 DNA, genes and chromosomes
4.2 DNA and protein synthesis
4.3 Genetic diversity can arise as a
result of mutation or during meiosis
4.4 Genetic diversity and adaptation
Required practical 6
4.5 Species and taxonomy
4.6 Biodiversity within a community
4.7 Investigating diversity
,AQA A Level Biology Topic 4 Genetic information, variation & relationships between organisms stan.store/biologywitholivia
4.1 DNA, genes and chromosomes
Compare and contrast DNA in eukaryotic cells with DNA in prokaryotic cells
Similarities:
● Nucleotide structure is identical - deoxyribose attached to phosphate and a base
● Adjacent nucleotides joined by phosphodiester bonds, complementary bases joined by hydrogen bonds
● DNA in mitochondria / chloroplasts have similar structure to DNA in prokaryotes
○ Short, circular, not associated with proteins
Differences:
● Eukaryotic DNA is longer
● Eukaryotic DNA is linear, prokaryotic DNA is circular
● Eukaryotic DNA is associated with histone proteins, prokaryotic DNA is not
● Eukaryotic DNA contain introns, prokaryotic DNA does not
What is a chromosome?
● Long, linear DNA + its associated histone proteins
● In the nucleus of eukaryotic cells
What is a gene?
A sequence of DNA (nucleotide) bases that codes for:
● The amino acid sequence of a polypeptide
● Or a functional RNA (eg. ribosomal RNA or tRNA)
What is a locus?
Fixed position a gene occupies on a particular DNA molecule.
Describe the nature of the genetic code
Triplet code A sequence of 3 DNA bases, called a triplet, codes for a specific amino acid
Universal The same base triplets code for the same amino acids in all organisms
Non-overlapping Each base is part of only one triplet so each triplet is read as a discrete unit
Degenerate An amino acid can be coded for by more than one base triplet
2
, AQA A Level Biology Topic 4 Genetic information, variation & relationships between organisms stan.store/biologywitholivia
What are ‘non-coding base sequences’ and where are they found?
Non-coding base sequence - DNA that does not code for amino acid sequences / polypeptides:
1. Between genes - eg. non-coding multiple repeats
2. Within genes - introns
In eukaryotes, much of the nuclear DNA does not code for polypeptides.
What are introns and exons?
Exon Base sequence of a gene coding for amino acid sequences (in a polypeptide)
Intron Base sequence of a gene that doesn’t code for amino acids, in eukaryotic cells
Exam insight: common mistakes ❌
Mistake Explanation
“Bacteria / prokaryotic cells have Chromosomes are found in eukaryotic cells. Bacteria have small,
chromosomes.” circular DNA not associated with histones.
“Prokaryotic DNA is single stranded, and This describes RNA. Prokaryotic DNA is double stranded and made
contains uracil instead of thymine. of exactly the same nucleotides as eukaryotic DNA (with A, T, C, G).
“Triplets produce amino acids.” Triplets code for amino acids, but don’t directly produce them.
“A gene is a section of DNA that This is too vague. A gene is a sequence of DNA (nucleotide) bases
codes for proteins.” that codes for a polypeptide (or functional RNA).
“An intron is a non-coding region This is correct, but not enough to get a mark. You must state what it
of a gene.” is that introns don’t code for, ie. amino acids.
“An exon codes for a protein.” This is too vague. An exon is a base sequence of a gene coding for
amino acid sequences (in a polypeptide).
3
Los beneficios de comprar resúmenes en Stuvia estan en línea:
Garantiza la calidad de los comentarios
Compradores de Stuvia evaluaron más de 700.000 resúmenes. Así estas seguro que compras los mejores documentos!
Compra fácil y rápido
Puedes pagar rápidamente y en una vez con iDeal, tarjeta de crédito o con tu crédito de Stuvia. Sin tener que hacerte miembro.
Enfócate en lo más importante
Tus compañeros escriben los resúmenes. Por eso tienes la seguridad que tienes un resumen actual y confiable.
Así llegas a la conclusión rapidamente!
Preguntas frecuentes
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
100% de satisfacción garantizada: ¿Cómo funciona?
Nuestra garantía de satisfacción le asegura que siempre encontrará un documento de estudio a tu medida. Tu rellenas un formulario y nuestro equipo de atención al cliente se encarga del resto.
Who am I buying this summary from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller sanhiahussain. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy this summary for 5,64 €. You're not tied to anything after your purchase.
