(Chapter 1.1) Genetics and biotech: DNA and the genetic code Flashcards
What does DNA stand for?
Deoxyribonucleic acid
True or False - Every organism has DNA
True
Who is credited for the discovery of DNA?
Watson and Crick
Which female made a significant contribution to DNA?
Rosalind Franklin
Define nucleic acid
Large biopolymers, macromolecules that play essential roles in all cells and viruses
Identify the main component(s) of a nucleotide
Nitrogenous base, 5-carbon-sugar, and phosphate group
Identify the nitrogenous bases in DNA
Adenine, Cytosine, Guanine, and Thymine
Identify the pairing of nitrogenous bases in DNA
Adenine - Thymine
Cytosine - Guanine
Identify the nitrogenous bases that are classified as purines
Adenine and Guanine
Identify the nitrogenous bases that are classified as pyrimidine
Cytosine and Thymine
Why are adenine and guanine the 2 larger nitrogenous bases?
Adenine and guanine are the 2 larger nitrogenous bases as purines have a 2-ring structure
What does RNA stand for?
Ribonucleic acid
Identify the nitrogenous bases in RNA
Adenine, Cytosine, Guanine, and Uracil
Identifying the pairing of nitrogenous bases in RNA
Adenine - Uracil
Cytosine - Guanine
Define chromosome
A thread-like structure of nucleic acids and protein found in the nucleus of most living cells. Composed of a singular DNA molecule
Identify the structure of DNA
2 polynucleotides coiled around each other to form the famous double-helix
Define DNA
A polymer that consists of 2 polynucleotide chains that coil around each other to form the famous double helix, carrying genetic instructions for organisms and various viruses
Identify 2 nucleic acids
DNA and RNA
Identify the number of pairs of chromosomes in an average human
23
True or False: The number of chromosomes is not necessarily an indication of organism complexity
True
True or False: The number of chromosomes is not necessarily an indication of organism complexity
True
Define gene
A unit of heredity, which is transferred to descendants, that determines a few characteristics of the descendant
Define karyotype
One’s complete set of chromosomes
Arrange the following structures in ascending order: Cell, Chromosome, Gene, Nucleic Acid, Nucleotide and Protein
Nucleotide, Nucleic Acid, Gene, Chromosome, Protein and Cell
Define DNA replication
The biological process of producing 2 identical replicas of DNA from the original DNA strand
What bonds the nitrogenous bases together in nucleic acids?
Hydrogen bonds
Identify the role of the helicase
The helicase ‘unzips’ the DNA
Identify the role of the DNA polymerase
The DNA polymerase synthesises the nitrogenous bases on the coding strand and ‘proofreads’ its work
Contrast template and coding strand
The template strand is the original strand and is the
template for the coding strand, which is the newer strand
True or False: Replication is the first stage of both mitosis and meiosis
True
Define centromere
The region of a chromosome to which the microtubules of the spindle fibres attach, through the kinetochore, during cell division. Or in English, the intersection of 2 chromatids in cell division
Identify the types of cell division
Mitosis and meiosis
Define chromatid
1 identical chromosome that has been replicated in preparation for cell division
Identify the role of Okazaki fragments
The Okazaki fragments assist the polymerase in sythnesising the coding strand by dividing the strand into segments as the polymerase cannot sythnesise continuously
What is the formal name for body cells?
Somatic cells
Define diploid
2 sets of chromosomes
Define haploid
A singular set of chromosomes
Define homologus pairs
Corresponding pairs of chromosomes that contain the same genes, but not necessarily the same alleles
What is the formal name for sex cells?
Gametes
Identify the role of the 23rd pair of chromosomes
The 23rd pair of chromosomes decide the gender of the offspring
Role of mitosis
Growth and repair in multicellular organisms
Identify the phases of mitosis
(Interphase,) Prophase, prometaphase, metaphase, anaphase, and telophase
True or False: Interphase is a phase in cell division
False
Describe prophase
Prophase is the first phase of mitosis, in which the duplicated chromatin, which is contained in the nucleus, condenses
Define chromatin
The material of which the chromosomes of organisms other than bacteria consists of protein, RNA, and DNA
Describe prometaphase
Prometaphase is the second phase of mitosis, in which the nuclear envelope breaks down and spindle fibres are formed.
Define nuclear envelope
A lipid bilayer membrane in eukaryotic cells that surrounds the nucleus
Identify the term nuclear envelope is also known as
Nuclear membrane
Describe metaphase
Metaphase is the third phase of mitosis, in which the chromosomes align themselves into a singular line in the centre of the cell
Define spindle fibres
Threads that form a protein structure that equally divides the genetic material in a cell
Describe anaphase
Anaphase is the fourth phase of mitosis, in which the chromatids separate at the centromere and are pulled to opposite ends of the cell by the spindle fibers
Role of kinetochore
The kinetochore assists the spindle fibres attach to the chromatids
Describe telophase
Telophase is the fifth phase of mitosis, in which the 2 daughter cells are formed
True or False: Both the parent and daughter cells in mitosis are diploid
True
Identify the phases of meiosis
(interphase,) Prophase I, metaphase I, anaphase I, telophase I, cytokinesis, (interphase II,) metaphase II, anaphase II, and telophase II
Identify the major phases of meiosis
Meiosis I and Meiosis II
Identify whether somatic cells are haploid or diploid
Diploid
Identify whether gametes are haploid or diploid
Haploid
Visually, identify features that show whether the cell is at the phase of meiosis I or II
If there is a singular cell, then it is in the phase of meiosis I. If there is 2 cells, then it is in the phase of meiosis II
Describe the process of meiosis
Basically, repeat the phases of mitosis twice
Role of meiosis
A type of cell division that occurs in germ cells to form 4 gametes
Outline the process of the development of male gametes
It starts off with a spermatagonium, which undergoes mitosis to form another spermatagonium and primary spermatocyte. Then, the primary spermatocyte undergoes meiosis to form 4 spermatids, which develop to become sperm
Outline the process of the development of female gametes
It starts off with a primordial follicle, which contains an oocyte and granulosa cells. Then, the primordial follicle undergoes mitosis and grows in size. Then, the primordial follicle undergoes meiosis to form a matured egg and 3 undeveloped eggs
Define germ cell
Cells that create/develop in reproductive cells
Define mutation
Changes in the structure of a gene, resulting in a variation, caused by the alteration of single base units in DNA, or the deletion, insertion, or rearrangement of larger sections of genes or chromosomes.
Why are mutations relatively rare?
The polymerase’s ‘proofreading abilities’ ensures there are minimal errors
Define amino acids
Molecules in (poly)peptides that form protein
Define peptide
A string of amino acids
Define codon
A sequence of 3 nucleic acids DNA or RNA
Describe the link between amino acids and codons
An amino acid is coded by the codon
Define mutagens
A physical or chemical agent that causes mutations
Outline somatic mutation
A mutation that occurs during mitosis in somatic cells
Outline germ-line mutation
A mutation that occurs during meiosis in germ cells, during the formation of gametes. Doesn’t impact the individual but is heritable
Identify the genotype of females
XX
Identify the genotype of males
XY
Identify the types of RNA
mRNA(messenger), rRNA(ribosomal), and tRNA(transfer)
Identify the role of mRNA(messenger)
mRNA carries protein blueprint from a cell’s DNA to a ribosome
Identify the role of rRNA(ribosomal)
rRNA reads the order of amino acids and links amino acids together
Identify the role of tRNA(transfer)
tRNA decodes an mRNA (messenger) sequence into a protein
