Unit 3 - Protein synthesis Flashcards
what is DNA
DNA is a deoxyribonucleic acid
a polymer of nucleotides which was formed by dehydration synthesis
DNA
what are the 3 major functions of DNA
- DNA controls cellular activities
- DNA makes exact copies of itself
- DNA undergoes mutations
DNA is the source of ____
the unity of life
Life most likely began as a ____
nucleic acid
the first form of life was____
a self replicating strand of RNA
Explain how there are different species on earth
DNA mutations - different combinations of DNA sequences due to mutations and sexual reproduction
When did the DNA double helix discovered?
1953
what is a nucleotide composed of?
- a pentose sugar
- a phosphate group
- a nitrogenous base
what are the two types of bases
Purines and Pyrimidines
what are the differences between Purines and Pyrimidines
Purines have a double nitrogen ring structure while Pyrimidines have a single nitrogen ring structure.
what are the two nucleotide bases with double ring structures
Adenine and Guanine
what are the two nitrogen bases with single ring structures
Thymine and Cytosine
Uracil but that’s only for RNA
what are the complementary base pairing between strands?
Adenine bonds with Thymine
Guanine bonds with Cytosine
how are Purines and Pyrimidines linked together?
by hydrogen bonds
how many hydrogen bonds are in the complementary base pairings
A-T = 2 hydrogen bonds G-C = 3 hydrogen bonds
what is Chargaff’s Rule?
the number of Purine Bases equals the number of Pyrimidines bases
what does the sequence of the bases determine?
it codes heredity information in the genetic code in DNA and RNA
Every human cell contains about one meter of DNA which amounts to ____ pairs of bases
four billion
what is a Gene
units of inheritance that control particular characteristics or capabilities of an organism
where are genes located
on the chromosomes
what does a gene consist of
a sequence of about 1000 DNA base pairs
how many genes compose the DNA molecule of a single human chromosome
175,000
genes always occur in ___
pairs
what do Genes control
cellular chemical reactions
how do genes control cellular chemical reactions
by directing the formation of enzymes
what are chromosomes held together by?
proteins called histones
before a cell can divide, what must occur
All of the DNA must be duplicated
what is the duplication process called
replication
each new strand of DNA produces has ________
a sequence of bases exactly complementary to the template strand
what is a template strand
the parental strand
each new stand of DNA contains _______
one “old” strand and on new strand
When DNA is replicated and contains one “old” strand and a new strand, what is this process called?
semi conservative replication
why does semi conservative replication happen prior to cells dividing
so that each new daughter cell receives the same genetic material as the parent cell
what is the genetic material of some viruses?
RNA
what is a necessary process to occur for all living organisms
protein synthesis
What does RNA consist off
Nucleotides
What is a RNA nucleotide composed of?
- a 5-carbon sugar called ribose
- a phosphate group that is attached to one end of the sugar molecule
- one of several different nitrogenous bases
there’s one base that is different from DNA, the base _____
Uracil
what does Uracil replace?
Thymine
RNA is not a double helix because….
it’s single stranded
what are the 3 types of RNA
- Ribosomal RNA (rRNA)
- messenger RNA (mRNA)
- transfer RNA (tRNA)
What is the function of DNA
it controls cellular activity, replication and can undergo mutations
What is the function of rRNA
ribosomal RNA combine with a protein to form ribosomes, and aid in the protein synthesis
What is the function of mRNA
messenger RNA copies sections of a DNA template strand
what is the function of tRNA
transfer RNA carries the amino acid from the cytoplasm to a ribosome for protein synthesis
where do you find hydrogen bonds in DNA
in the middle between the bases
where do you find covalent bonds in the DNA strand
along the phosphate and sugar group
what is the difference between Purines and Pyrimidines
Purines have a double nitrogen ring structure while Pyrimidines have a single nitrogen ring structure
what are the three components of a nucleotide?
a pentose sugar, phosphate group and a nitrogenous base
If a nucleotide has 20% Thymine, how much does a Gaunine base make up?
30%
explanation: Thymine equals 20% which means Adenine equals 20% leaving 60% lets over divided amongst Gaunine and Cytosine
What is chargaff’s rule?
the number of Purine bases equals the number of pyrimidine bases
What are the pairings in a DNA molecule
A-T, C-G
what are the pairings in RNA
A-U, C-G
what are the pairings in mRNA
A-U,C-G
what are the pairings in tRNA
A-U, C-G
what is semi conservative replication?
when each new strand of DNA produced contains one “old” strand and one new strand
what is the role of helicase
the enzyme helps the H- bonds between the two strands of DNA break
what is the role of DNA polymerase
helps H-Bonds form between template and complementary strand
What is the function of RNA polymerase
it’s involved in transcription
what is a gene
genes are the units of inheritance that control particular characteristics or capabilities of an organism
where is a gene located
genes are located on the chromosomes of the cell nucleus
what is the function of a gene
genes control cellular chemical reactions by directing the formation of enzymes
what is the structure of DNA
double stranded / double helix
what nucleic acid is single stranded
RNA
what is the function of the bases
they function as the the fundamental units of the genetic code
what are the three steps of translation
Initiation, elongation, and termination
what is the steps of transcription
H bonds in the DNA unzip, and the sense strand of the DNA combined with the complementary RNA bases, and the DNA molecule requires fa and returns to its normal double helix form
where does RNA get made?
in the nucleus
How big is a codon
3 letters long
how many different codons are there?
64
what is a codon
a 3 letter unit of mRNA which codes for one amino acid
what is a anticodon
a base sequence that is complementary to the codon
where is an anticodon found?
on tRNA
what are the three types of mutagens?
Chemical, Radiation and Viral
what causes chemical mutagens?
pesticides, food additives, MSG, acetone, benzene, and cigarette smoke
what causes radiation mutagens
UV light, X rays, and gamma rays
what causes viral mutagens
HPV
what happens during initiation
the small rRNA subunit first attaches to the start codon on the mRNA, then a tRNA anticodon pairs with the codon, where the large rRNA subunit then joins with the small subunit
what occurs during elongation
more amino acids are added and connected together to form a polypeptide as a specified by the mRNA sequence.
what occurs during termination
elongation repeated until a special codon called a stop codon is reached
what are the three stop codons
uaa, uag, uga
where does transcription occurs
the nucleus
where does the translation occur
the ribosome
what is a gene mutations
a mutation which affects only one gene; small scale but can have devastating effects
what is chromosomal mutations
a mutation which affects many genes because they affect entire chromosomes or parts of chromosomes
what is a somatic mutation
a mutation which occurs in body cells after birth e.g cancer
what is a germinal mutation
a mutation of the gametes or early in the development of the embryo
what are the three types of gene mutations
addition, substitution or deletion
what are the four different types of chromosome mutations
inversion, translocation, duplication, deletion
what are the two worst types of mutations
addition and deletion which can lead to frame shift mutations
what is a polysome
a cluster of ribosomes held together by a strand of messenger RNA that each ribosome is translating.
what are the three major enzymes
RNA polymerase, DNA polymerase and Helicase
what type of mutation is this…
a b c d e f g l m n o p q r ——->
a b c d e q r l m n o p f g
translocation
what type of mutation is this…
a b c d e f g ——-> a b c d e d e f g
duplication
what type of mutation is this?
a b c d e f g ——> b c d e f g
deletion
describe the bond strength in a DNA molecule
a hydrogen bond which hold pairs of bases together, is weak, which is why the covalent bonds which hold the backbone together is very strong
what is a pyrimidine
One of two chemical compounds that cells use to make the building blocks of DNA and RNA. Examples of pyrimidines are cytosine, thymine, and uracil.
what is a purine
the building blocks of dna and rna molecules. examples are adenine and guanine
what is replication
replication is the process by which a double-stranded DNA molecule is copied to produce two identical DNA molecules.
what is transcription
Transcription is the process by which the information in a strand of DNA is copied into a new molecule of messenger RNA (mRNA).
what is translation?
the process in which mRNA is made into amino acids
what is DNA ligase
DNA ligase is a specific type of enzyme, a ligase, that facilitates the joining of DNA strands together by catalyzing the formation of a phosphodiester bond.
what is a ribosome
The ribosome is a complex molecule made of ribosomal RNA molecules and proteins that form a factory for protein synthesis in cells.
what is a gene mutation
an alteration in the nucleotide sequence of the genome of an organism, virus, or extrachromosomal DNA.
what is substitution
when a nucleotide is substituted or replaced by another nucleotide
what is addition
when a nucleotide or multiple nucleotides are added
what is deletion
when a nucleotide or multiple nucleotides are deleted out of the amino acid sequence
what is chromosomal mutation
Chromosome mutation is the process of change that results in rearranged chromosome parts, abnormal numbers of individual chromosomes, or abnormal numbers of chromosome sets.
what is inversion
An inversion is a chromosome rearrangement in which a segment of a chromosome is reversed end to end.
what is translocation
A genetic change in which a piece of one chromosome breaks off and attaches to another chromosome. Sometimes pieces from two different chromosomes will trade places with each other.
what is duplication
when a piece or pieces of the chromosome are duplicated or doubled
what is a mutagen
any factor that can cause a mutation
what is a carcinogen
a mutagen that causes cancer
what is a vector
A vector is a living organism that transmits an infectious agent from an infected animal to a human or another animal.
what is a plasmid
A plasmid is a small, circular, double-stranded DNA molecule that is distinct from a cell’s chromosomal DNA.
