DNA: The code of life Flashcards
What part of the nucleus disappears during prophase of mitosis (1.3.2)
Double nuclear membrane, nucleolus, ER, ribosomes
Name two functions of the cell nucleus (1.4)
The chromosomes in the nucleus store the genetic material of the cell
It regulates the structure and activities of the cell
Why do think gregor mendel is the father of genetics? (2.1)
He was the first person who performed heredity experiments using pea plants and who found that each heredity characteristic is controlled by a specific gene
Name the 2 Nucleic acids (name and abbreviation) that occur in a cell? (3.1)
DNA- deoxyribonucleic acid
RNA- ribonucleic acid
Are Nucleic Acids considered to be inorganic or organic molecules. Explain your answer? (3.2)
Organic- It contains the element carbon
What are the monomers (building blocks) of nucleic acids called? (3.3)
Nucleotides
Name the sugar molecules that occur in DNA (3.5.1) and RNA (3.5.2)
DNA- deoxyribose
RNA-ribose
Name the different nitrogenous bases that occur in DNA (3.6.1) and RNA (3.6.2)
DNA- Adenine, Thymine, Guanine, Cytosine
RNA- Adenine, Uracil, Guanine, Cytosine
What is the natural shape of RNA? (3.8.2)
Single stranded which may be straight or folded
To which group of organic compounds does RNA belong to? (8.3.2)
Carbohydrates
Name the 3 types of RNA found in a cell? (8.4)
mRNA, tRNA, rRNA
Briefly describe the structure of mRNA (8.5.1)
It consists of a single strand with an unlimited number of nucleotides and nitrogenous bases in any order. each group of three nitrogenous bases is known as a codon
What is the difference between prokaryotic and eukaryotic cells
Prokaryotic cells have no nucleus so DNA is found in the cytoplasm, they are the oldest living organisms, DNA is enclosed in a membrane (DNA in plasmid) and no membrane bound organelles.
Eg. Bacteria
Eukaryotic cells contain membrane bound nuclei and other organelles, DNA forms part of the chromosomes. Eukaryotic cells also contain extra- nuclear DNA that forms outside the nucleus in mitochondria and chloroplasts for plants.
what is the function of the double nuclear membrane on the nucleus
encloses the nucleus and isolates its contents from the cytoplasm, it is a differentially permeable membrane and controls movement of substances in and out the nucleus
what is the function of the nuclear pores on the nucleus
regulate transport of protein and RNA molecules across the 2 membranes
what is the function of the nucleolus
Is mainly involved in the assembly of ribosomes
what is the function of the chromosomes
contain DNA which provides the genetic information for the protein synthesis to control metabolism and structure of cell. Also carries heredity information.
What are the functions of the cell nucleus
regulates the metabolism of the cell
DNA controls the production of enzymes (proteins that catalyse all reactions that occur in the cell) and therefore it controls the processes that occur in the cell
regulate the structure of the cell
carries the heredity characteristics of the cell + organism (DNA carries genes that each determine a characteristics)
what is a monomer
it is a building block
what is a nucleotide
the monomer which forms DNA and RNA
what is nuclear DNA?
DNA found in the nucleus
what is heredity?
Genetic information passed on from parent to offspring
what are histones?
proteins that form part of the chromosomes
what is a gene?
A section or chemical structure of DNA in a chromosome, which carries a code about a particular characteristic in an organism.
what is a brief history of DNA
1865–Gregor mendel finds that each characteristic in his plant pea experiments is
controlled by a gene.
1952 – Rosalind Franklin and her assistant Maurice Wilkins researched the structure of DNA using X-ray diffraction images.
Watson and Crick did independent research on DNA. Upon seeing Franklin’s images,
they proposed a 3-D double helix model for DNA in 1953.
1962 – Watson and Crick received the Nobel Prize for the discovery of the structure of
DNA, and Wilkins received an award for his X-ray photography. Franklin had died of cancer.
where is DNA located?
DNA is located in the nucleus of the cell part of the chromosome structure. DNA is also located outside the nucleus called Extra-nuclear DNA which is known as Chloroplastic DNA and Mitochondrial DNA
what is the structure of the DNA
DNA has a double helix structure, where the double helix (backbone) is made of histones (proteins) and consists of monomers called nucleotides that form long chains called polymers.
what is the role of DNA
DNA carries hereditary information in the form of genes.
Controls the functioning of cells
Regulate the functioning of genes
Passes on hereditary characteristics
what is non-coding DNA
DNA strands that do not code for anything
when and where does DNA replication occur
Replication of DNA occurs in the chromosomes found in the nucleus During interphase of the cell cycle/ mitosis
what is the process of DNA replication
The 2 strands of the double helix structure unwinds.
The weak hydrogen bonds break and the 2 DNA strands unzip/ separate.
Each DNA serves as a template in which its complement is built.
Free-floating DNA nucleotides from the pool in the nucleoplasm in the nucleus, attach to their complementary nitrogenous base pairs.
This results in two identical DNA molecules. Each molecule consists of one original strand and one new strand.
what is the biological importance of DNA replication
DNA consists of its own synthesis to ensure the exact copying of DNA before mitosis occurs- both daughter cells will have the same DNA as the mother cell.
The nucleus of each somatic cell in your body thus has an identical DNA composition.
Replication ensures that the heredity information in the original chromosome is passed on during mitosis when the mother cell forms the identical daughter cells
What are the advantages of a DNA profile
DNA can be linked to one person- every persons DNA is unique.
DNA can be stored and used many years after a crime had been committed
Only a small amount of DNA is necessary to prepare a profile
What are some disadvantages of a DNA profile
Need well qualified technologists to operate
People can be framed by people placing DNA at a crime scene and can also be at the crime scene accidentally
It invades privacy of the victim and the suspect
What is the structure, location and function of RNA
Single stranded Sugar is ribose Adenine, guanine, cytosine and uracil Bases can present any ratio Found in nucleus+cytoplasm Forms part of the ribosomes
What are the 3 types of RNA
Messenger RNA- produced in the nucleus and acts as a template (code for amino acid sequence)
Transfer RNA- carries the specific amino acids to the ribosomes in protein synthesis. One transfer RNA for each triplet codon that codes for a specific amino acid. Clover shaped. They have an anticodon that is complementary to the triplet codon on the messenge RNA.
Ribosomal RNA- make up the ribosome. Which becomes a site for protein synthesis.
Describe transcription of protein synthesis
Stage 1 of protein synthesis
@the double helix unwinds
@the double stranded DNA unzips/weak hydrogen bonds break
@to form two separate strands
@one strand is used as a template
@to form mRNA
@using free nucleotides from the nucleoplasm
@the mRNA is complementary to the DNA
@mRNA now has the coded message for protein synthesis
@mRNA moves from the nucleus to the cytoplasm and attaches to the ribosome.
Describe translation of protein synthesis
Stage 2 @each tRNA carries a specific amino acid @when the anticodon on the tRNA @matches the codon on the mRNA @then tRNA brings the required amino acid to the ribosome. Amino acids become attached by peptide bonds @to form the required protein
