DNA, The Code of Life Flashcards
nucleic acids
organic molecules that controls the synthesis of proteins in all living cells by storing and transferring genetic information
where does DNA occur and what does it form
the nucleus where it forms part of the chromatin network/chromosomes
what is extranuclear DNA
DNA that occurs outside the nucleus in small amounts
define histones
proteins that DNA is wrapped around
define genes
short segments of DNA molecules that codes for a particular protein
what is the function of genes
each gene carries the code for synthesis of a particular protein which determines the characteristics of an organism
what are the monomers of DNA called
nucleotides
what are the three parts of the DNA nucleotides
deoxyribose sugar
phosphate group
nitrogenous base
what are the four nitrogenous bases of DNA
adenine
guanine
cytosine
thymine
which two nitrogenous bases are known as purine and why
adenine and guanine, because they are large
which two nitrogenous bases are known as pyrimidine and why
cytosine and thymine because they’re smaller molecules
how many hydrogen bonds does adenine and thymine have
2
how many hydrogen bonds do guanine and cytosine have
3
how is DNA formed
the deoxyribose sugar of one nucleotide forms a bond with a phosphate of another
the nitrogenous bases are joined by weak hydrogen bonds that are easily broken by enzyme action
why is the sequence of nitrogenous bases so important
it provides the code that gives the instructions for the synthesis of proteins.
what is the role of DNA
- to carry genetic information
- to replicate and ensure the genetic code is accurately transferred
when does DNA replication take place
during interphase
process of DNA replication
- double helix structure unwinds
- weak hydrogen bonds break and the two DNA strands unzip
- free-floating nucleotides in the nucleoplasm builds a complementary DNA strand onto the two original DNA strands
what is the importance of DNA replication
to ensure each daughter cell contains the same genetic information as the mother cell
what is DNA profiling used for
- identifying crime suspects
- proof of paternity
- determining the probability of genetic defects
where does RNA occur?
the nucleus and cytoplasm
what does RNA form part of
ribosomes
what are the 4 nitrogenous bases of RNA
- adenine
- guanine
- cytosine
- URACIL
how is RNA formed
when nucleotides join, the ribose of one nucleotide attaches to the phosphate group of another to form a single strand.
function of mRNA
to carry the genetic code from DNA in the nucleus to the ribosomes in the cytoplasm
function on tRNA
to pick up amino acids in the cytoplasm and take them to the ribosomes where protein synthesis occurs
function of rRNA
forms part of the ribosomes in the cytoplasm and plays a role in protein synthesis
what is protein synthesis
when proteins are made in living cells
where does protein synthesis take place
at the ribosomes in the cytoplasm
what controls protein synthesis
DNA and RNA
define base triplet and what do they determine
three consecutive nitrogenous bases on the DNA strand
they determine which of the amino acids will link which thus determines what protein is contructed
define transcription
where mRNA obtains the code for protein synthesis from DNA
define translation
the processing of the code locked in the mRNA strand to form a certain amino acid sequence in the synthesis of a particular protein
