Bio Sem 2 Unit 2 Exam Rev Flashcards
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The structure of DNA
Phosphate group
Deoxyribose sugar
Nitrogenous Bases - Guanine, Cytosine, Thymine, Adenine
Name the 3 distinct chemical components in the nucleotide
A sugar molecule (either ribose in RNA or deoxyribose in DNA) attached to a phosphate group and a nitrogen-containing base.
Understand the difference between DNA and RNA
DNA has a deoxyribose sugar while RNA has a Ribose sugar
DNA is a double helix while RNA is a single-strand
DNA has Thymine while RNA has Uracil
The general steps to produce a protein from DNA
- Transcription - DNA is read and transcribed by the RNA polymerase into a single-strand RNA with Thymine being changed to uracil, producing pre-mRNA
- RNA editing - Introns are removed, Exons are spliced together - produces mRNA
- Translation - The mRNA is translated by the tRNA into a polypeptide protein chain
What is the DNA and RNA base pairing rules
DNA
Adenine = Thymine
Guanine = Cytosine
RNA
Adenine = Uracil
Guanine = Cytosine
If DNA sequence is:
ACCAAACCGAGT
Find out the mRNA sequence
UGGUUUGGCUCA
What are the functions of
rRNA, mRNA, tRNA
rRNA - Makes up 60% of the ribosome; site of protein synthesis
mRNA - Carries the code from DNA that specifies amino acids used in translations (mesenger RNA)
tRNA - Carries a specific amino acid to ribosome, based on its anticodon to mRNA codon
Define Transcription, where and how does it occure?
Transcription is the process in which DNA is transcribed into a single strand pre - mRNA
All this happens in the nucleus of a cell
Define RNA processing, where and how does it occure
RNA processing or RNA editing is when the RNA polymerase takes in the pre-mRNA and removes the introns and splices together the exons to create a mature mRNA.
This happens in the nucleus of a cell - Transcription
How does nucleic acids encode the instructions to make proteins
The mRNA sequence used as a template to assemble the chain of amino acids that form a protein
What is the difference between a triplet, codon, and anticodon?
Anticodon - A section of 3 bases that are from the tRNA
Codon - A section of 3 bases that are from the mRNA
Triplet - A section of 3 bases
Define Gene structures
- Exons
- Introns
- Promoter
- Operator regions
Exons - Parts of the pre-mRNA that is kept and spliced together to form the mature mRNA
Introns - Parts of the pre-mRNA that is removed (unecessary)
Promoter - section of DNA where RNA polymerase binds and transcription begins
Operator - section of DNA where proteins that control transcription bind
Describe the benefits of gene regulation e.g lac operon
Allows cells to react quickly to changes in their environments.
What are the components of a protein
- polypeptide chain of amino acid monomers
Explain the connection between DNA, Genes, Chromosomes and Alleles
Chromosomes are a threadlike structure of nucleic acids and protein, carrying genetic information (DNA) in the form of genes
Gene is a section of DNA that carries the code to make a protein - determines the trait
Alleles are alternative forms of gene
Define homologous chromosome
Pairs of chromosomes that have same genes and chromosome size
Define Sister chromatid
Identical copies of a chromatid that are held together by centromere
Define Centromere
The middle of the Chromosome that holds the chromatids together
Define Locus
The location of one gene on a chromosome
Loci - multiplie genes on a chromosome
The difference between genes, alleles and genomes?
Genome is all of the DNA in an organism, gene is a section of DNA, Alleles are different forms of genes
Difference between autosomes and sex chromosomes
Autosomes are chromosomes that determine the traits of an organism while sex chromosome determines the gender of an organism
How do we read a Karyotype
First 22 sets of chromosomes are autosomes
Last set (23rd) is sex chromosome
Describe the 5 main types of asexual reproduction
- Binary fission - bacteria cells - splits from 1 cell to 2 cells once
- Budding - Small bud grows out of parent, Two different sized structures made with identical DNA, Bud can breaks off and grow into new organism
- Fragmentation - A piece of an organism breaks off and forms an individual organism containing the same DNA
- Vegetative propagation - occurs in plants, in which a new plant grows from a fragment or cutting of the parent plant
- Sporogenesis (Spore Formation) - The process of formation of spores - has same DNA as parent spores
List 3 Advantages and Disadvantages of asexual reproduction
Advantages of asexual reproduction
- Increased speed in population growth
- offsprings are identical therefore fine-tuned to it’s environment
- Does not require much energy due to not needing to find a mate
Disadvantages of asexual reproduction
- Lacks the ability to adapt to new environment
- Disease may affect all the individuals in a population.
- The organisms produced have shorter lifespans.