Luokat: Kaikki - mutation - meiosis - protein

jonka Rida Sorfina 4 vuotta sitten

714

mutation

Changes in chromosome number or structure can lead to significant genetic alterations. These mutations often occur during meiosis, particularly during anaphase, when non-disjunction events may result in aneuploidy, where cells have extra or missing chromosomes.

mutation

mutation

chromosomal mutation

CHROMOSOMAL ABERRATION change in structure
CHRMOSOMAL NUMBER ALTERATIONS change in number

ANEUPLOIDY

chromosomal EXTRA or MISSING from normal set

cause-non-disjunction during meiosis (anaphaseI,II) non-disjunction-failure of a homologous chromosomes or sister chromatid to separate and move to opposite poles

occur in autosome and sex-chromosomes

eg: 2n-1monosomy,2n+1trisomy

EUPLOIDY/POLYPOIDY

has more than two sets of chromosomes (more common in plant)

3n,4n,5n,

occur naturally(by non-disjunction or induction)

form new species better qualities

alloploidy

individual has more than two chromosomes sets that derived from different species

autoploidy

individual has more than two chromosomes sets that all derived from same species

Definition
changes in chromosomal structure or chromosomal number

gene mutation/ point mutation

type
base inversion

More than one nucleotide breaks, rotate 180 and reattached to the DNA

base deletion

Loss of one or more nucleotide pair from the DNA

base insertion

Addition of one or a more nucleotide pair into the DNA

frameshift mutation

base substitution

one nucleotide pair is replaced with another nucleotide pair in the DNA sequence

lead- silent, missense, nonsense mutation

NONSENSE MUTATION

changes mRNA into a stop codon

translation terminated produce shorter polypeptide

lead to non-functional proteins

MISSENSE MUTATION

cause frameshift mutation

amino acid changes to another amino acid

results in ONE WRONG CODON and ONE WRONG AMINO ACID in polypeptide

less active protein

eg: SICKLE CELL ANEMIA(RBC shape like a crescent)

symptoms sickle cell anemia

*Hb-stiff, tend to accumulate at blood capillary *fatal form of anemia *organ damages *physical weakness

DNA- CTT replaced CAT mRna-codon GAA replaced GUA polypeptide- glutamic acid replaced valine

SILENT MUTATION

base substitution nucleotide pair of DNA has no effect on the encoded protein

change in nucleotide but translated same amino acid

changes codon on mRNA codes for the same amino acid

result
changes of codon in mRNA. Hence, change the amino acid sequence and the protein.Different protein produced may not function as normal
due
mistake in base pairing during DNA replication
definition
changes in the nucleotide base pairs in a gene