B1 Variation and Inheritance 0.0 / 5 ? BiologyVariation and InheritanceGCSEOCR Created by: 11HBickhamCreated on: 24-05-16 19:26 What are variations? Differences between individual of the same species 1 of 33 Why do genetic variations occur? because individuals inherit different combinations of genes 2 of 33 What can genetic inheritance be caused by? mutations (changes the the genes), differences between individual gametes (ie. eggs and sperm), the random nature of fertilisation 3 of 33 what can varations other than genetic be? environmental 4 of 33 What are two examples of genetic variation? nose shape and eye colour 5 of 33 What are two examples of environmental variation? language and scars 6 of 33 What are three examples of combination variation? body mass, intelligence and height 7 of 33 Where are all the instructions to make an individual held? on chromosomes kept in the nucleus of all body cells 8 of 33 What is the section of chromosome which codes for an inherited characteristic or protein called? a gene 9 of 33 How many pairs of chromosomes does a person have? 23 10 of 33 How many chromosomes do gametes? gametes have half the number of chromosomes of normal body cells 11 of 33 What are the different versions of genes called? alleles 12 of 33 What are alleles that control characteristics described as being dominant or or recessive? dominant or recessive 13 of 33 What do dominant alleles control? the development of a characteristic even if present on only one chromosome in a pair 14 of 33 What do recessive alleles control? the development of a characteristic only if a dominant allele isn't present 15 of 33 What is the person described as if both chromosomes in a pair contain the same allele of a gene? homozygous for that gene or condition 16 of 33 What is the person described as if the chromosomes in a pair contain different alleles? heterozygous for that gene or condition 17 of 33 What is a monohybird inheritance? when a characteristic is determined by just one pair of alleles, as with eye colour and tounge rolling 18 of 33 What are capital letters used to represent? dominant 19 of 33 What are lower case letters used to represent? recessive 20 of 33 What are letters to describe the genetic make-up called? genotype 21 of 33 Gender (in mammals) is determined by the what? sex 22 of 33 What do egg cells carry? all X chromosomes 23 of 33 What do sperm cells carry? half carry X and half carry Y chromosomes 24 of 33 What is the sex of an individual depend on? whether the egg is fertilised by an X- or Y- carrying sperm 25 of 33 An egg fertilised by an X sperm will become a what? girl (X from egg and X from sperm = **) 26 of 33 An egg fertilised by an Y sperm will become a what? boy (X from egg and Y from sperm = XY) 27 of 33 What is the chance of having a girl or boy? 50:50 28 of 33 If a disease is caused by a 'faulty' gene then what can they be? inherited 29 of 33 What is three examples of 'faulty' gene diseases? red-green colourblindness, sickle cell anaemia, cystic fibrosis 30 of 33 Why may having an inherited disease create issues? may not know whether to have kids, or to abort an affected foetus 31 of 33 What are inherited disorders are mostly caused by? recessive faulty genes 32 of 33 What does it mean that the gene for cystic fibrosis is recessive? that offspring will only have the disorder if both genes are faulty 33 of 33
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