Basic Genetics Flashcards
What is included in nucleic acid
- a nucleic acid is a long chain of nucleotides
* each nucleotide consists of a phosphate group, a 5-sugar and a nitrogenous base.
What are the bases inside the DNA ?
- adenine (A)
- Thymine (T)
- Cytosine (C)
- Guanine (G)
What are the bases in RNA ?
- Adenine (A)
- Uracil (U)
- Cytosine (C)
- Guanine (G)
How is the composition of DNA different from that of RNA?
- The sugar in DNA is deoxyribose whereas that in RNA is ribose.
- The bases in DNA are adenine (A), thymine (T), cytosine (C) and guanine (G). In RNA, T is replaced by uracil (U)
- A DNA molecule is double-stranded, while a RNA molecule is single-stranded
Describe the Watson-Crick model of DNA
•A DNA molecules consists of two polynucleotide chains. The two chains run in a opposite directions and twist to form a double helix.
•complementary base pairing:
~A of one chin pairs only with T of another chain by hydrogen bond and C with G
What is gene ?
- Gene is the basic unit of heredity.
- the base sequence of DNA in a gene determine the sequence of the amino acid in a polypeptide in way called genetic code
What is the structural relationship between a chromosome, DNA and a gene?
- Chromosomes are made up of DNA and proteins.
* A gene is a segment of the DNA molecule on a chromosome.
How do genes determine the body characteristics of an organism?
•The base sequence of DNA in a gene determines the amino acid sequence in a polypeptide and hence the types of proteins a cell makes. This in turn determines the body characteristics of an organism.
Why is DNA well suited to its function as a genetic material?
- DNA is a large molecule consisting large no. of nucleotide. This allow DNA to carry a large amount of genetic information.
- DNA is a stable molecule. The helical structure is maintained by many hydrogen bond between two strand.
- the pairing of specific base enables accurate replication of DNA so that the same genetic information can be passed from generation to generation.
How does a DNA molecule replicate?
- the two DNA strand are held together by weak hydrogen bond between the bases.
- the hydrogen bond break and the two DNA strand separate.
- each DNA strand act as a template for the synthesis of a new DNA polymerase catalysts the addition of free nucleotide to each template.
- two identical DNA molecules are formed. Each contains an original strand and a new strand.
What is Mendel’s first law of inheritance or law of segregation ?
During gamete formation( ie. meiotic cell division), alleles sesperate so that each gamete receives only one allele from each pair
What is monohybrid inheritance?
It is the inheritance of a single characteristic controlled by single gene
What is Mandel first law or law of segregation?
• during gamete formation (meiotic cell division), alleles separate so that each gamete receives one allele from each pair.
What is dihybrid inheritance?
Dihybrid inheritance is the inheritance of two pairs of contrasting characters at the same time. It involves two genes on different chromosomes.
What does the Law of Independent Assortment state?
It states that the separation of alleles for one gene is independent of the separation of alleles for other genes during gamete formation.
