In prokaryotic cells, what is the shape of the DNA molecule and is it associated with proteins?
Short circular DNA not associated with histone proteins.
Prokaryotes lack histones and typically have a single circular chromosome in the cytoplasm.
In the nuclei of eukaryotic cells, DNA molecules are long and linear. Which proteins are they associated with to form chromosomes?
Histones
DNA wraps around histone proteins to form chromatin, which condenses into chromosomes.
What structure is formed when a DNA molecule combines with its associated proteins in eukaryotic cells?
Chromosome
A chromosome consists of one long DNA molecule packaged with proteins.
Besides the nucleus, which two organelles in eukaryotic cells also contain their own DNA?
Mitochondria and chloroplasts
These organelles have circular DNA similar to that found in prokaryotes.
True or False:
DNA in mitochondria and chloroplasts is linear and associated with histone proteins.
False
Their DNA is short, circular and not associated with histone proteins, similar to prokaryotic DNA.
What do we call a sequence of DNA bases that codes for a polypeptide or a functional RNA molecule?
Gene
Genes can code for polypeptides or functional RNA such as rRNA and tRNA.
What term describes the fixed position that a gene occupies on a DNA molecule?
Locus
Each gene is located at a specific locus on a chromosome.
What is the name given to a sequence of three DNA bases that codes for a specific amino acid?
Triplet or codon
Each triplet of DNA bases corresponds to one amino acid in a polypeptide.
True or False:
The genetic code is overlapping, meaning a base can belong to multiple triplets.
False
The genetic code is non-overlapping, so each base is part of only one triplet/codon.
What property of the genetic code means that several different base triplets can code for the same amino acid?
Degenerate
For example, multiple codons can specify the same amino acid.
Fill in the blank:
Within a gene, the sequences that actually code for amino acid sequences are called ______.
Exons
Exons remain in the mature mRNA after RNA processing.
Fill in the blank:
Non-coding sequences found within genes that separate coding regions are called ______.
Introns
Introns are removed during RNA splicing before translation occurs.
True or False:
Much of the DNA in eukaryotic nuclei does not code for polypeptides.
True
Eukaryotic genomes contain large amounts of non-coding DNA including repeats and introns.
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3.1.1 Monomers & Polymers9
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3.1.2 Carbohydrates22
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3.1.3 Lipids17
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3.1.4 Proteins39
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3.1.5 Nucleic Acids32
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3.1.6 ATP11
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3.1.7 Water11
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3.1.8 Inorganic ions8
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3.2.1 Cell structure52
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3.2.2 Cell division20
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3.2.3 Transport across cell membranes20
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3.2.4 Cell recognition & the immune system36
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3.3.1 Surface area to volume ratio13
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3.3.2 Gas exchange24
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3.3.3 Digestion & absorption16
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3.3.4 Mass transport39
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3.4.1 DNA, genes & chromosomes13
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3.4.2 DNA & protein synthesis14
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3.4.3 Genetic diversity & meiosis14
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3.4.4 Genetic diversity & adaptation20
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3.4.5 Species & taxonomy20
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3.4.6 Biodiversity within a community12
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3.4.7 Investigating diversity12
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3.5.1 Photosynthesis23
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3.5.2 Respiration17
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3.5.3 Energy & ecosystems20
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3.5.4 Nutrient cycles15
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3.6.1 Stimuli & Response62
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3.6.2 Nervous coordination53
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3.6.3 Skeletal muscles14
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3.6.4 Homeostasis57
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3.7.1 Inheritance12
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3.7.2 Populations15
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3.7.3 Evolution may lead to speciation22
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3.7.4 Populations in ecosystems24
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3.8.1 Gene Mutations and Protein Structure14
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3.8.2 Control of Gene Expression44
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3.8.3 Applications of Genome Projects10
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3.8.4 Gene Technologies and Their Applications46
