Genetic Information, Variation, And Relationships Between Organisms (8) Flashcards
What is a gene?
A section of DNA that contains the coded information for making polypeptide and functional RNA
What is a chromosome?
A long strand of DNA that is wrapped around histone proteins
What is a locus?
A specific place in the chromosome where a gene is found
How many chromosomes are there in the human body cell ?
46
How many pairs of chromosomes are there in a human cell?
23 pairs
How many sets of chromosomes are there in a human body cell?
2
How many sets of chromosomes are there in an egg cell/sperm cell?
1 set
Where does each chromosome in a homologous pair come from?
One set from mother and other set from father
Why do males have a different number of homologous Pairs of chromosomes to females?
Males have 22 homologous pairs as XY and females have 23 as XX
How can we define the term homologous pair of chromosomes?
2 chromosomes, same position of locus on their chromosome;not the same genes
What is an intron?
A section of DNA that doesn’t code for proteins
What is an exon?
A section of DNA that does code for proteins
Do prokaryotic cells have intron?
No
Does humans have intron?
Yes
Do all organisms have exons?
Yes
DNA found in mitochondria and chloroplasts are similar to what type of DNA, prokaryotic or eukaryotic?
Prokaryotic
DNA codes for?
The sequence of amino acids in proteins produced by the cell
Why is the genetic code known as a triplet code?
3 bases code for a single amino acid
A gene is transferred between different organisms and still code for the same polypeptide - what does this tell is about the genetic code?
It is universal
How many triplet codes are there all together?
64
How many different amino acids are there in proteins?
20
Some triplet codes don’t code for amino acids, what do they code for instead?
Stop triplet
Why do most amino acids have more than one triplet code?
More triplet codes - 64 compared to the 20 amino acids
Why would different polypeptides have different structure and functions?
Different sequence of amino acids - different primary structures
What does degenerate mean?
Most amino acids are coded by more than 1 triplet
What is a start triplet?
Codes for Met and start of the polypeptide
What is a stop triplet?
Does not code for amino acids, only the end of the polypeptide
What does it mean by non-overlapping?
Each base can only be a part of 1 triplet
What does the term universal mean?
Each triplet codes for the same amino acids in all organisms
