Dna Flashcards
What did James Watson and Francis Crick do? And what award did they receive?
- James Watson and Francis Crick formulated the double helix structure of DNA using a 3D model.
- They revived the Noble Prize for the discovery of the structure of DNA.
What did Rosalind Franklin?
She discovered the helical structure of DNA, through an image that she took.
What % of DNA in living cells Code for Proteins, what does the rest do?
- 2% of DNA in living cells code for proteins.
- the other 98% is called non-coding DNA, and is used in DNA fingerprinting.
Define a gene.
A short segment of DNA that codes for a particular trait.
Discuss the structure of a DNA Nucleotide.
- Sugar Molecule - Deoxyribose
- Phosphate group
- Nitrogenous base (four types)
What are the Nitrogenous bases found on DNA nucleotide?
Large purine bases:
- Adenine
- Guanine
small pyrimidine base:
- Cytosine
- Thymine
What are the three Exposed bases on tRNA called?
-anticodon
What are the three exposed bases on mRNA called?
-codon
Define a homologous Chromosome:
Two chromosomes of the same size and shape, that contain the identical genes.
What are the steps in DNA Replication?
- DNA Unwinds.
- Helicase break weak hydrogen bonds (unzips DNA strand)
- Free Nucleotides build complementary DNA strand.
- DNA polymerase join free nucleotides to their complementary base pair.
- New Strands are formed!!
Define a Gonosome:
- Sex determining Chromosome
Define an Autosome:
- Non-Sex determining chromosome
What is the difference between Haploid and Diploid?
- Haploid cells are those that only have a single set of chromosomes (n)
- Diploid cells have two sets of chromosomes (2n)
What is Meiosis?
A type of cell division that produces 4 haploid gametes from 1 diploid cell.
What are proteins made up of?
- Proteins are made up of amino acids.
In Protein synthesis, what provides the code for a particular amino acid?
- Base triplets provide a code for a particular amino acid
- base triplets determine sequence in which amino acids will link
What is the role of DNA?
- The role of DNA is to carry the genetic code for the synthesis of proteins.
What are Nucleic acids?
- what are the different types?
Nucleic Acids are organic molecules that control the synthesis of proteins and transferring of genetic info.
- Deoxyribonucleic Acid (DNA)
- Ribonucleic Acid (RNA)
What are the two different types of DNA and where are they found?
Chromosomal DNA -> occurs mainly in the nucleus where it forms chromosomes
Extranuclear DNA -> small amounts are found in the mitochondria and in the chloroplast.
Discuss the structure of DNA:
- Large molecules consisting of two strands twisted to form a double helix.
- polymer made up of monomers (nucleotides)
- total length ~ 2m
Where does RNA occur?
- RNA occurs in the nucleus, cytoplasm and parts of the ribosomes.
What is mtDNA?
- where does it occur?
- what does it look like?
- what does it code for?
- Mitochondrial DNA
- occurs in the mitochondria
- is circular in shape
- gene of mtDNA codes for the enzymes that control cellular respiration.
How are the DNA‘s nitrogenous bases joined?
- the nitrogenous bases are joined by weak hydrogen bonds.
Base Pairs:
Adenine (A) - Thymine (T)
Cytosine (c) - Guanine (G)
How are RNA‘s Nitrogenous bases joined?
Adenine (A) - Uracil (U)
Cytosine (C) - Thymine (T)
What is protein synthesis?
- a process in which proteins are manufactured in living cells.
What controls the synthesis of proteins?
- DNA and RNA control the synthesis of proteins.
What are the two steps in protein synthesis?
-Transcription
-Translation
Discuss the structure of RNA
- Single Strand made up of unlimited nucleotides
Discuss the structure of an RNA nucleotide:
- sugar molecule (ribose)
- phosphate group
- Nitrogenous bases
Large Purine bases:
- Adenine
- Guanine
Small pyrimidine bases:
- Cytosine
- Uracil
What is synapsis
When two homologous pairs are coming together.
What is bivalent
When homologous pairs lie next to one another.
Why is DNA replication important?
- it is essential that DNA replicate itself before cell division to ensure that each daughter cell has identical DNA to the mother cell.
Define the phenotype:
- the phenotype is the observable physical or biochemical characteristics of an organism.
How is the phenotype determined?
- the phenotype is determine by an organisms genotype interacting with environmental factors.
Define Genotype:
- the genotype is the genetic makeup of an organism, representing certain alleles it possesses for a particular trait.
Define chromosomes:
A threadlike structure of nucleic acids and protein found in the nucleus of most living cells, carrying genetic info.
What is mRNA?
- where is it found
- what is it’s structure
- what does it do
Messenger RNA
- found in the nucleus and cytoplasm or a cell.
- single strand with unlimited nucleotides
-carries genetic code from DNA in nucleus to ribosomes in cytoplasm.
What is tRNA?
- where is it found
- what is it’s structure
- what does it do
Transfer RNA
-occurs in cytoplasm
-single strand that folds in on itself to form loops.
- picks up amino acids and takes them to the ribosome.
What is rRNA?
- what is it’s structure
Ribosomal RNA
- single strand that forms part of ribosome structure
What is transcription:
- Transcription is the process of copying a segment of DNA into RNA for the purpose of gene expression
Describe steps in transcription
- DNA unzips where gene is located
- RNA polymerase cause hydrogen bonds to break, and control the transfer of code from DNA to RNA
- Free-floating RNA nucleotides are used to build complementary strand
- single mRNA strand is formed
- DNA strands retwist, mRNA leaves nucleus via nuclear pores.
Describe steps in translation:
- mRNA strand attaches to ribosomes and provides genetic code for amino acids
- anticodon determines what amino acids will bind to tRNA
- tRNA picks up amino acids
- tRNA places amino acids in sequence
- Amino acids join together to form polypeptide chain
- process continues till 50 or more amino acids are joined.
