dna & genetics Flashcards
(30 cards)
what is the function of the nucleus?
control centre of the cell contains inherited information in the form of dna
what is the function of the nucleolus?
make the small parts or subunits, which make up the ribosomes. The nucleolus makes the subunits from ribosomal RNA and proteins
what is the function of the nuclear pores?
they regulate the movement of molecules from the nucleus into the cytoplasm and allows Rna to leave the nucleus.
what is the function of the ribosomes?
the site of protein synthesis
what is an organelle?
a membranous structure within a cell, specialised for a particular function
what is a cell?
the basic structural and functional unit of a living organism
what does the DNA model look like?
double helix (twisted ladder)
what is DNA?
deoxyribonucleic acid - the chemical compound that carries the inherited information in the cell
what is the basic structure of DNA?
- its made up of repeating units of nucleotides
- consists of a deoxyribose sugar, a phosphate and nitrogenous base
- double stranded
what are nucleotides made up of?
a deoxyribose sugar, a phosphate and nitrogenous base
what are the 4 nitrogenous bases?
adenine, thymine, cytosine & guanine
what are the base pairs?
A & T
C & G
how are complimentary coded strands created?
the nitrogenous bases pair up to form the rungs (twisted ladder). The 4 bases all have different chemical structures which means that they can only pair up one way, known as complimentary base pairing
what is a gene?
the factor that determines an inherited characteristic, located in the chromosomes
what are chromosomes?
a rod-like structure that contains DNA, which makes up the genes of an individual
what is the relationship between DNA, genes & chromosomes?
DNA is stored in the nucleus as chromosomes. A chromosome consists of segments of DNA known as genes
what are the functions of DNA?
- Carry genetic information for inheritance, requiring DNA replication
- Contains the instructions for ribosomes to produce proteins in protein synthesis
what does DNA in chromosomes do?
code for particular inherited characteristics
what is evolution?
The gradual change in the characteristics of a species over a period of time
what is natural selection?
The process by which a species becomes better adapted to its environment
what is the theory of evolution by natural selection?
- mutations in the DNA code can lead to variations in populations
- more offspring are produced than can survive due to selection pressures
- some traits/variations are more favourable in the environment (survival of the fittest)
- favourable traits are passed onto the next generation
what is survival of the fittest?
individuals with the most favourable traits in a particular environment will have a survival advantage
what is an allele?
an alternative version of a specific gene
what does dominant mean?
where one allele masks the effect of the alternative allele
