genetics Flashcards
what does DNA stand for?
deoxyribonucleic acid
what are the four base in DNA?
Adenine
Thymine
Guanine
Cytosine
draw a diagram of a section of DNA?
what is the definition of chromosome ?
a single chain of DNA that has been coiled up into a thread like structure
Define the term gene?
a specific section within DNA which codes for a specific protein
what are introns ?
non coding genes that regulate gene expression
what are exons ?
coding genes for DNA
what is semi conservative replication ?
the original double stranded will divide into two parent stands and then join with a new strand
what is the process of unwinding ?
DNA helicase breaks the hydrogen bonds between the nucleotide
the point after which the strands are separated is known as the replication fork
what does DNA polymerase do ?
collect nucleotides and matches them with the complimentary pairs on the parent strand running a 5-3 prime direction
what is the leading strand ?
the strand that is replicating in the direction of unwinding
what is the lagging strand?
strands replicating in the reverse direction
what does Primase do?
creates short segments of primers which bind to make up the sections of DNA
what are individual section of primers called ?
Okazaki fragments
what does DNA ligase do ?
a glue that seals the nucleotides together to make a continuous strand
what is the cell cycle ?
Gap 1
Synthesis
Gap 2
Mitosis
what is the process of mitosis ?
IPMAT
what is interphase ?
cell growth
production of organelles
DNA replication
produces proteins necessary for mitosis
what is prophase ?
chromosomes condense and become visible
each chromosome is comprised of 2 chromatids
spindle fibres begin to form
nuclear membrane begins to form
what is metaphase?
chromosomes line up along the equator
what is anaphase?
spindle fibres attach to the centromeres
spindle fibre pull chromatids to opposite pole of the cell
what is telophase ?
chromatids group together
2 new nuclear membranes for
chromosomes unravel
Cytokinesis occurs
what is cytokinesis in animals ?
membranes move inwards pinching two daughter cells apart
what is cytokinesis in plants ?
cell membrane and wall is created
what is the role of DNA?
to provide the blue prints for proteins
what is different about RNA to DNA?
made of ribose sugar instead of deoxyribose
single stranded instead of double
uracil instead of thymine
normally shorter the DNA
what does transcription make ?
mRNA
what is the process of transcription?
- a small section of DNA is unwound and the hydrogen bonds are broken by helicase to expose the nucleotides
- RNA polymerase goes along and picks up free nucleotides and binds it to the complimentary base to form the mRNA
- RNA polymerase and the mRNA detaches whilst the DNA zips back up
-mRNA exits the nucleus through a nuclear pore.
what prime does RNA polymerase run and why ?
3-5 prime
so add RNA nucleotides instead of DNA nucleotides
where does RNA polymerase start and stop?
Promoter sequence
Terminator sequence
what is the methylated cap?
- an alter nucleotide that binds to the 5’ end
-acts as a signalling molecule that can be reached by ribosomes
What is the poly A-tail?
- a sequence of many adenosines joined to the 3’ end
-help stabilise and protect the mRNA
what is splicing ?
the process of removing introns and joining exons together
what is alternating splicing?
controls which exons are spliced together
what is translation?
the process of creating proteins from a template in the ribosome
what is the process of translation?
-the methylated cap allow the ribosome to attache to mRNA
-the ribosome reads three nucleotides at time called a codon
-tRNA then get the anticodon that matched the codon
-the tRNA has amino acids that join together to form polypeptide chains
-the polypeptide the coils up to for proteins
what is meiosis?
the process where a single cell divide twice to form 4 daughter cells.
what is the process of meiosis?
Prophase 1
metaphase1
anaphase 1
telophase 1
cytokines 1
Prophase 2
metaphase 2
anaphase 2
telophase 2
cytokines 2
what is prophase 1 ?
-homologous chromosomes pair up
what is metaphase 1?
-homologous pairs line up on the equator
-spindle fibres attach
what is anaphase 2?
-homologous chromosomes pulled to seperate side of the cell
-chromosomes copy and go to one side
what is telophase 1?
2 haploid cells begin to formed