Biology Molecular Genetics
Molecular Genetics -DNA -DNA Replication -RNA -Protein Synthesis -Transcription; Translation
Molecular Genetics -DNA -DNA Replication -RNA -Protein Synthesis -Transcription; Translation
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Alexandra Elia
Alexandra Elia
This flashcard set covers fundamental concepts of molecular genetics at the secondary school level. It delves into the structure and function of DNA, RNA, and proteins, explaining processes like transcription, translation, and DNA replication. The set also explores the genetic code, types of RNA, and the differences between DNA and RNA, providing insights into the flow of genetic information and the impact of replication errors. Ideal for students seeking a comprehensive understanding of molecular genetics, this flashcard set offers clear explanations and practical examples to enhance learning.
DNA (what does it look like? of what does it exist?)
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- nucleic acid made of two long chains of repeating subunits --> nucleotides
- the two chains (or strands) wrap around each other in the form of a double helix
DNA nucleotides
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- consist of three parts:
- deoxyribose (five-carbon sugar)
- phosphate group
- nitrogenous base
- connected by covalent bonds between sugar of one nucleotide and phosphate group of the next nucleotide
- hydrogen bonds
- connect nitrogenous bases of one strand with those of the other strand
- help hold the two strands together
Nitrogenous bases
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- purines (double ring): adenine & guanine
- pyrimidines (single ring): cytosine & thymine
- base-pairing-rules:
- the bases are complementary --> purine pairs always with pyrimidine
- cytosine + guanine
- adenine + thymine
- order of nitrogenous bases : base sequence
DNA replication
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- process, by which DNA is copied in a cell before it divides
- two nucleotide strands separate along the strands
- each strand serves as a template to make a new complementary strand
- after replication the two identical new DNA molecules separate and move to the new cells formed during cell division
Prokaryotic & Eukaryotic Replication
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- Prokaryotic
- one circluar chromosome
- replication begins at one place along chromosome
- two replication forks proceed in opposite directions
- Eukaryotic
- long chromosome, but not circular
- replication begins at many points ("origins") along DNA
- two replication forks moving in opposite directions
Errors in replication
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- DNA polymerases have repair functions that "proofread" DNA
- change in the nucleotide sequence of a DNA molecule --> mutation:
- can have serious effects on the function of an important gene and disrupt an important cell function
- can lead to diseases (e.g. cancer)
Flow of genetic information (in an eukaryotic cell)
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- Transcription
- DNA acts as a template for the synthesis of RNA
- Translation
- RNA directs assembly of proteins
- Protein Synthesis (/gene expression)
- Forming of proteins based on information of DNA --> carried out by RNA
Differences DNA & RNA
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- RNA
- nucleic acid made up of nucleotides
- sugar: ribose
- nitrogenous bases: uracil, guanine, cytosine, adenine
- single stranded
- much shorter than DNA (length of one gene)
- DNA
- also made up of nucleotides
- sugar: deoxyribose
- nitrogenous bases: thymine, guanine, cytosine, adenine
- double stranded
- contains thousands of genes
Types of RNA
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- three major types; each plays a different role in protein synthesis
- messenger RNA (mRNA)
- carries the instructions from a gene to make a protein
- ribosomal RNA (rRNA)
- part of the structure of ribosomes (--> organelles in the cell where protein synthesis occurs)
- transfer RNA (tRNA)
- transfers amino acids to the ribosome to make a protein
- messenger RNA (mRNA)
Transcription
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process, by which genetic instructions in a specific gene are transcribed into an RNA molecule
The Genetic Code
- term for the rules that relate how a sequence of nitrogenous bases in nucleotides corresponds to a particular amino acid
- three-nucleotide sequence: codon:
- encodes an amino acid
- signifies a start or stop signal
- start codon: specific sequence of nucleotides that indicates where translation should begin
- stop codon: signal for translation to end
Translation
- the making of a protein
- "decoding of the genetic instructions to form a polypeptide"
- protein: made of one or more polypeptides (polypeptides: chains of amino acids linked by peptide bonds)
The Human Genome
- genome: complete genetic content
- important because learning which gene sequences control particular biological functions may help diagnose, treat and prevent genetic disorders, cancer and more diseases in the future
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Flashcards
DNA (what does it look like? of what does it exist?)
- nucleic acid made of two long chains of repeating subunits --> nucleotides
- the two chains (or strands) wrap around each other in the form of a double helix
DNA nucleotides
- consist of three parts:
- deoxyribose (five-carbon sugar)
- phosphate group
- nitrogenous base
- connected by covalent bonds between sugar of one nucleotide and phosphate group of the next nucleotide
- hydrogen bonds
- connect nitrogenous bases of one strand with those of the other strand
- help hold the two strands together
Nitrogenous bases
- purines (double ring): adenine & guanine
- pyrimidines (single ring): cytosine & thymine
- base-pairing-rules:
- the bases are complementary --> purine pairs always with pyrimidine
- cytosine + guanine
- adenine + thymine
- order of nitrogenous bases : base sequence
DNA replication
- process, by which DNA is copied in a cell before it divides
- two nucleotide strands separate along the strands
- each strand serves as a template to make a new complementary strand
- after replication the two identical new DNA molecules separate and move to the new cells formed during cell division
Prokaryotic & Eukaryotic Replication
- Prokaryotic
- one circluar chromosome
- replication begins at one place along chromosome
- two replication forks proceed in opposite directions
- Eukaryotic
- long chromosome, but not circular
- replication begins at many points ("origins") along DNA
- two replication forks moving in opposite directions
Errors in replication
- DNA polymerases have repair functions that "proofread" DNA
- change in the nucleotide sequence of a DNA molecule --> mutation:
- can have serious effects on the function of an important gene and disrupt an important cell function
- can lead to diseases (e.g. cancer)
Flow of genetic information (in an eukaryotic cell)
- Transcription
- DNA acts as a template for the synthesis of RNA
- Translation
- RNA directs assembly of proteins
- Protein Synthesis (/gene expression)
- Forming of proteins based on information of DNA --> carried out by RNA
Differences DNA & RNA
- RNA
- nucleic acid made up of nucleotides
- sugar: ribose
- nitrogenous bases: uracil, guanine, cytosine, adenine
- single stranded
- much shorter than DNA (length of one gene)
- DNA
- also made up of nucleotides
- sugar: deoxyribose
- nitrogenous bases: thymine, guanine, cytosine, adenine
- double stranded
- contains thousands of genes
Types of RNA
- three major types; each plays a different role in protein synthesis
- messenger RNA (mRNA)
- carries the instructions from a gene to make a protein
- ribosomal RNA (rRNA)
- part of the structure of ribosomes (--> organelles in the cell where protein synthesis occurs)
- transfer RNA (tRNA)
- transfers amino acids to the ribosome to make a protein
- messenger RNA (mRNA)
Transcription
process, by which genetic instructions in a specific gene are transcribed into an RNA molecule
The Genetic Code
- term for the rules that relate how a sequence of nitrogenous bases in nucleotides corresponds to a particular amino acid
- three-nucleotide sequence: codon:
- encodes an amino acid
- signifies a start or stop signal
- start codon: specific sequence of nucleotides that indicates where translation should begin
- stop codon: signal for translation to end
Translation
- the making of a protein
- "decoding of the genetic instructions to form a polypeptide"
- protein: made of one or more polypeptides (polypeptides: chains of amino acids linked by peptide bonds)
The Human Genome
- genome: complete genetic content
- important because learning which gene sequences control particular biological functions may help diagnose, treat and prevent genetic disorders, cancer and more diseases in the future
