Understanding Inheritance and Genetics in Organisms

1. Subtopic (b) Inheritance SQA questions

2. Inheritance WYSK enetic nformation arents • Certain characteristics are determined by g_______ i_________ received from both p_______ e.g. furc______ , blood g______, stem l_______ and shape of l______ or seeds • Each inheritedcharacteristic can appear in a number of forms called p__________. • Phenotype is the a__________ of an individual • An organism which is t________ b________ e.g. TT or gg produces only o___ type of gamete e.g. _ or _ • The F1 offspring of a true breeding cross have u_______ phenotype – all the same olour roup ength eaves henotypes ppearance rue reeding ne T g niform

3. ominant ecessive onohybrid • A d_________ gene or phenotype always shows • A r__________ gene or phenotype can be hidden • A m__________ cross is between two true breeding parents which have d_______ phenotypes of the s_______ characteristic E.g. Black (BB) x brown (bb) • The symbol for parental generation is __ • The symbol for first offspring is __ • The symbol for second offspring is __ • The expected ratio in F2 is _____ ( ¾ : ¼ ) • Expected ratios don’t always happen because f____________ is a r_________ process ifferent ame P F1 F2 3 : 1 ertilisation random

4. ne ffspring amete ne • A parent contributes o___of the two forms of a gene to their o________ • A g________ is a sex cell which carries o___ of the two forms of a gene • Gametes contain a s________ set of chromosomes • Body cells contain a d________ set of chromosomes – t___ matching sets • The r_________ in the number of chromosomes occurs at g_______ formation • At fertilisation chromosome numbers d________ when the m_____ nucleus and the female n_______ fuse together ingle ouble wo eduction amete ouble ale ucleus

5. wo ene enes • A g____ is part of a chromosome.T___ formsof a gene control each inheritedcharacteristic • The genotypeis all the g______ an organism contains. Its genetic m____ - up. • A______ is the name given to the two forms of a gene • The __ and ___ chromosomes determine sex • ___ is male and ___ is female • The male gamete (s______) may contain an __ or a __ chromosome • The female gamete (e___) always contains an ___ chromosome ake llele X Y XY XX perm X Y X gg

6. G Llama and camel successfully interbreed to produce baby Scientists believe he will be infertile XY XX XX XY

7. G tongue rolling sex blood groups ear lobes Presence of operation scars

8. G √ gametes √ doubled √

9. G horns F1

10. G BB bb Bb BB or Bb bb gold body black body black body

11. G 4 : 1 84 black body : 21 gold body Divide by 21: 84÷ 21 21 ÷ 21 = 4 : 1

12. G √ discontinuous gametes

13. G taster non taster √

14. G Use the letters Tfor tasting and t for non tasting to show the forms of gene present in the sex cells of Rab and Audrey t t

15. G gametes √ X Y X X Down’s syndrome

16. G X X X Y female male F1

17. G genotype gamete variation

18. G Two/double Two/double one/single one/single Two/double gametes fertilisation

19. G X X X Y XX XY female female

20. C discontinuous Arranged in distinct / clear cut groups

21. C 195 yellow seeds + 65 purple seeds = 260 seeds % yellow : 195÷ 260 = 0.75 X 100 = 75% 75% alleles radiation

22. C GG Gg ¼ of 72 = 18 black ¾ of 72 = 54 grey 54 18

23. C Fertilisation is a random process alleles

24. C TT tt Tt 3 1

25. C 4 1 Fertilisation is a random process

26. C alleles bb Bb Fertilisation is a random process

27. C bb Same coat colour discontinuous

28. C RR rr Rr Rr 1RR : 2Rr : 1rr all none some

29. C ratio is 3 red : 1 white 1488 ÷ 3 = 496 white 496 Fertilisation is a random process Rr rr

30. C alleles Can be arranged into distinct (clear cut) groups