Back to AI Flashcard MakerBiology /A-level Biology - 3.1.7 DNA, Genes and Chromosomes Part 2

A-level Biology - 3.1.7 DNA, Genes and Chromosomes Part 2

Biology32 CardsCreated about 2 months ago

This deck covers key concepts in DNA structure, replication, and genetic coding, focusing on differences between eukaryotic and prokaryotic DNA, gene expression, and chromosome structure.

Describe stage 3 of semi-conservative replication

Condensation reactions join nucleotides - catalysed by enzyme DNA polymerase H bonds form between bases (on original and new strands)

Back side illustration
Tap or swipe ↕ to flip
Swipe ←→Navigate
1/32

Key Terms

Term
Definition

Describe stage 3 of semi-conservative replication

Condensation reactions join nucleotides - catalysed by enzyme DNA polymerase H bonds form between bases (on original and new strands)

Describe stage 4 of semi-conservative replication

Each new DNA molecule contains one strand from original DNA molecule and one new strand (Double strand twists again)

Eukaryotic DNA is & _ with ______
Nuclear Eukaryotic DNA is Linear & Associated with Proteins
What is a DNA molecule in eukaryotic cells wound around?
(Proteins called) histones
What do histone proteins do?
Help support the DNA

DNA molecules and histone are coiled up very tightly to make _ ________

compact chromosomes

Related Flashcard Decks

Study Tips

  • Press F to enter focus mode for distraction-free studying
  • Review cards regularly to improve retention
  • Try to recall the answer before flipping the card
  • Share this deck with friends to study together
TermDefinition

Describe stage 3 of semi-conservative replication

Condensation reactions join nucleotides - catalysed by enzyme DNA polymerase H bonds form between bases (on original and new strands)

Describe stage 4 of semi-conservative replication

Each new DNA molecule contains one strand from original DNA molecule and one new strand (Double strand twists again)

Eukaryotic DNA is & _ with ______
Nuclear Eukaryotic DNA is Linear & Associated with Proteins
What is a DNA molecule in eukaryotic cells wound around?
(Proteins called) histones
What do histone proteins do?
Help support the DNA

DNA molecules and histone are coiled up very tightly to make _ ________

compact chromosomes

___________ and ___ in eukaryotes have their own DNA
Mitochondria and chloroplast
What is the DNA in mitochondria and chloroplast (in eukaryotes) like?
Similar to prokaryotic DNA ∵ its circular and shorter than DNA in nucleus & it's not associated with histone proteins
What is DNA like in prokaryotic cells?
DNA molecules are shorter and circular & isn't wound around histones

How does prokaryotic DNA fit into cells?

Condenses to fit in cell by supercoiling

What is a gene?
Sequence of DNA bases that codes for either a polypeptide or functional RNA
What do different polypeptides have?
They have different no. and order of amino acids
What determines the order of amino acids in a polypeptide?
The order of bases in a gene

What is each amino acid coded by?

A sequence of 3 bases in gene = called triplet

What is functional RNA?
RNA molecules other than mRNA (e.g. tRNA & rRNA)
What is meant by a cell's genome?
The complete set of genes in the cell
What is meant by a cell's proteome?
Full range of proteins that the cell is able to produce
Most DNA in eukaryotic cells _ code for polypeptides
DON'T
In eukaryotic DNA, genes that code for _ contain sections that…
In eukaryotic DNA, genes that code for polypeptides contain sections that don't code for amino acids
What are introns?
Sections of DNA that don't code for amino acids
Can there be several introns within a gene?
Yes
What are exons?
Bits of gene that do code for amino acids
When are introns are removed?
During protein synthesis
Prokaryotic DNA doesn't have ____
introns
Eukaryotic DNA contains regions of _ _____ ____ of genes
Eukaryotic DNA contains regions of multiple repeats outside of genes
What are multiple repeats?
DNA sequences that repeated over and over again e.g. CCTTCCTTCCTT
Multiple repeats ____ code for amino acids & are called ______ ____
Multiple repeats don't code for amino acids & are called non-coding repeats
What is order of bases like in alleles and what does this lead to?
Order of bases in each alleles is slightly different ∴ they code for slightly different versions of the same polypeptide
What is homologous pair?
Pair of matching chromosomes: both chromosomes are same size & have same genes (BUT could have different alleles)

Where are alleles coding for the same characteristic found on chromsomes in a homologous pair?

Found at same fixed position (locus) on each chromosome in a homologous pair

Explain why DNA helicase is important in DNA replication (2)
Breaks H-bonds (So) nucleotides can attach/strands can act as templates

Draw 2 nucleotides joining together