Inheritance - Mutation

Question 1

What is mutations + causes

Answer 1

Random changes to bases in DNA structure - resulting in different protein created
-cancer, cell not working properly, adaptation

Mutagenic chemical (carcinogen), ionising radiation

If mutation is in gamete, not affect individual but the offspring

Question 2

Body safe guard against mutation

Answer 2

DNA polymerase- fit complementary base + proof read bases

Proto-oncogene - make sure cell only divide during mitosis or meiosis (fully matured)
-oncogene if mutated - cell divide when not suppose to = cancer

Tumour suppressant gene - suppresses cell division - if mutated cell can divide when not mature

Question 3

Gene mutations

Answer 3

Frame shift - errors in 1 base sequence that affects entire gene then code for wrong amino acid - lead to point mutation

Gene deletion - whole gene missing from chromosome

Substitution - a base replace with another
Inversion - 2 base swapped around
Addition - addition of another base
Deletion - a base deleted

Question 4

Outcome of gene mutation

Answer 4

Intron mutation - non-coding gene so nothing happens

Silent mutation - codon still code for same amino acid

Missense mutation- different amino acid created may cause protein to dysfunction

Nonsense mutation - stop codon removed or happened = peptide chain too long or short

Question 5

Gene mutations- sickle cell anaemia

Answer 5

Change in amino acid sequence chase haemoglobin change from biconcave to crescent shape

Question 6

Chromosomes mutation

Answer 6

-Duplication of gene in chromosome
-Position of gene inverted in chromosome - affects chiasma
-Translocation - different length of 2 chromosome exchange - 1 too long other too short

Aneuploidy - loss or gain of chromosome in homologous pair (3 chromosome in 21st pair cause Down’s syndrome - cause by nondisjunction gamete - 2 chromosome in gamete)

Polyploidy - total chromosomes number is ofd number (if 61 chromosome 1 cannot be homologous pair = no gamete formation)

Error in chiasma - chromosomes not in homologous pair exchange not like wise gene

Question 7

Cancer mutation

Answer 7

Cell not fully matured
-grow uncontrollably, wrong shape, chromosome number abnormal, large nucleus

Question 8

Somatic cell + gamate mutation

Answer 8

Somatic cell - cancer
-can’t pass cancer to offspring, but gene increasing risk can

Gamete mutations
-can pass down
-single gene mutation (sickle cell anaemia)
-chromosomal mutation (Down’s syndrome)