01 DNA, Chromosomes and Karyotypes Fit Flashcards
What is DNA?
A molecule that contains the genetic info needed to build and maintain an organism
What does DNA carry?
Hereditary information and instructions for cellular processes (what they cell is made of and what it does)
What is a gene?
A section of DNA that determines the characteristics of an organism.
What is hereditary information?
Genetic material that is passed on from one generation to the next
Where is DNA found?
In the chromosomes in the nucleus
What is a nucleotide?
The basic unit of DNA.
What is a nucleotide made up of?
A phosphate molecule, a deoxyribose sugar and a nitrogenous base
What are the 4 bases?
Adenine, guanine, thymine, cytosine
What forms the DNA backbone?
Phosphate molecule and deoxyribose sugar.
How are the base pairs linked together?
- One polynucleotide strand runs in opposite directions to its paired strand.
- They spiral around an imaginary axis to form a double helix
- The hydrogen bonds between the complementary base pairs bind the strands together
What is an allele?
Different forms of a single gene, found in the same loci (same position on same chromosome)
What is a genome?
The total of an organism’s DNA measured in the number of base pairs that make up the DNA in a single set (haploid) of chromosome
Gene expression
The process of using gene instructions to make proteins
What are the 2 stages of protein synthesis?
- Transcription: DNA is transcribed into RNA
- Translation: ribosomes read the nucleotide sequences in groups of 3 called codons.
What is a chromosome?
A structure made up of a single strand of DNA and proteins.
When are chromosomes visible?
During cell division in prophase
What do histone proteins do?
– maintain structure of chromosome
– organise the long strand of DNA
– controls the activity of genes so that only certain proteins can be produced
What is a nucleosome?
The basic unit of a chromatin, small packages formed by DNA wrapped around a histone
What is a locus?
The specific position of a gene on a chromosome (like a street address)
What is the function of a spacer DNA?
Keep genes apart so that enzymes and molecules can interact with genes.
What are the 2 arms of a chromosome?
p arm: short
q arm: long
What are the 4 types of chromosomes from shortest to longest?
Telocentric
Acrocentric
Submetacentric
Metacentric (both arms equal)
What is a matching pair of chromosomes called?
Homologous
What does each pair of homogolous chromosome contain?
One chromosome inherited from each parent
