D3.2 Inheritance

Question 1

autosomal

Answer 1

gene located on one of the numbered or non sex chromosomes.

Question 2

autosomal chromosome

Answer 2

numbered chromosomes in a karyogram ranged from smallest to largest

Question 3

gregor mendel

Answer 3

cross bred different types of pea plants in monastery

300,000 plants over 8 years
large sample carefully planned, easily recognisable characteristics

Question 4

parental generation (P)

Answer 4

first set of parents in a genetic cross. The parents genotypes are used to predict the genotype of their offspring

Question 5

monohybrid cross

Answer 5

cross involving one pair of contrasting characteristics exhibited by homozygous parents

Question 6

F1 generation

Answer 6

first finial generation
arises by crossing parents and when selfed or crossed via sibling crosses, produces the F2 generation

Question 7

F2 generation

Answer 7

offspring produced by F1 generation

Question 8

dominant allele

Answer 8

an allele that has the same effect on the phenotype whether it is present in the homozygous or heterozygous state

Question 9

recessive allele

Answer 9

an allele that has an effect on the phenotype only when present in the homozygous state

Question 10

punnet grid

Answer 10

diagram used to show and calculate all the combinations and frequencies of different genotypes and phenotypes among the offspring of a genetic cross

Question 11

Mendells conclusions

Answer 11

• breeding factors controling characteristics
• 2 factors in each cell
• one factor from each parent
• factor can be separated and passed during reproduction
• factor tall is dominant and alternative to factor dwarf

Question 12

law of segregation

Answer 12

pair of alleles segregate from each other during meiosis so that only one allele will be present in each gamete.

Question 13

genotype

Answer 13

the combination of alleles inherited by an organism. genetic constitution of organism

Question 14

homozygous

Answer 14

having 2 identical alleles of a gene

Question 15

heterozygous

Answer 15

having 2 different alleles of a gene

Question 16

phenotype

Answer 16

observable traits of an organism resulting from genotype and environmental factors

Question 17

organisms can have the same __ but different __

Answer 17

phenotype
genotype

Question 18

what can phenotype be determined by

Answer 18

genotype, environmental factors, interactions

eg. eyecolor and blood

Question 19

recessive characteristic in phenotype

Answer 19

homozygous genotype

Question 20

dominant characteristic

Answer 20

homozygous or heterozygous

may look alike but different genotypes

Question 21

phenotypic plasticity

Answer 21

the capacity to develop traits suited to the environment experienced by an organism by varying patterns of gene expression

ex. exercise result

Question 22

phenylkatonuria

Answer 22

a reccessive genetic condition caused by mutation in an autosomal gene that codes for the enzyme needed to convert phenylalanine to tryosine.

Question 23

untreated infants with PKU

Answer 23

unusually light eye, skin and hair colour

Question 24

high blood phenylalanine levels

Answer 24

disruptions in neurotransmiters such as dopamine

Question 25

symptoms of PKU

Answer 25

seizures, abnormal muscle movements, tight muscles and tremors can lead to sevre brain damage

Question 26

cure for PKU

Answer 26

phenylalanine restricted diet

Question 27

genotype for PKU

Answer 27

recessive

Question 28

carrier

Answer 28

an individual that has one copy of a recessive allele that causes a genetic disease in individuals that are homozygous from this allele

Question 29

single nucleotide polymorphisms

Answer 29

- represents a different in a single nucleotide - can replace C with A - many alleles can exist - an individual can only inherit 2 alleles rather than the full number

Question 30

blood groups

Answer 30

A B AB O

Question 31

co dominant blood groups

Answer 31

I^A and I^B

Question 32

co dominance

Answer 32

both alleles are expressed in a phenotype

Question 33

incomplete dominance

Answer 33

where a dominant allele does not completely mask the effects of a recessive allele resulting in heterozygotes having an intermediate phenotype

Question 34

what do sex chromosomes decide

Answer 34

gender

Question 35

sex of offspring is determined by

Answer 35

the male

Question 36

7th week of pregnancy

Answer 36

growth of genitalia if Y chromosome is present

Question 37

Y chromosome codes for a protien called

Answer 37

testis determining factor TDF

Question 38

testis determining factor functions

Answer 38

a molecular switch and initiates production of a low level of testosterone

Question 39

in the absense of Y chromosome

Answer 39

ovary formed under hormones from ovary develops female reproductive structures

Question 40

sex linkage

Answer 40

special case of linkage occuring when a gene is located on a sex chromosome usually the x chromosome

Question 41

which chromosome is longer

Answer 41

X

Question 42

alleles on Y are concerned with

Answer 42

male structures and functions

Question 43

eg of recessive conditions

Answer 43

red green color blindness haemophilia

Question 44

haemophilia

Answer 44

blood doesnt clot normally frequent and excessive bleeding due to failure to produce proper particular blood protiens

Question 45

genes for haemophilia are on which chromosome

Answer 45

X

Question 46

recessive or dominant for haemophilia

Answer 46

recessive

Question 47

haemophilia common in which gender

Answer 47

males

Question 48

when is haemophilia fatal

Answer 48

fatal in uterus to women - abortion

Question 49

analysis of pedigree charts

Answer 49

can be used to detect conditions due to dominant and recessive allels

Question 50

dominant in pedigree charts

Answer 50

dominant - more and more in every generation

Question 51

recessive in pedigree charts

Answer 51

recessive - infrequent and skips many generation

Question 52

albinism

Answer 52

rare and recessive monohybrid inheritance

Question 53

brachydactyly

Answer 53

fingers are very short usually allele is dominant so tends ro occur in every generation

Question 54

why is relative marraige prohibited mostly

Answer 54

probability is increased of child inheriting 2 copies of a harmful recessive allele rather than only one

Question 55

polygenic inheritance

Answer 55

inheritance of phenotypic characters that are determined by the collective effects of several different genes

Question 56

variation types

Answer 56

continuous and discontinuous

Question 57

combined effect of all genes

Answer 57

continuous variation

Question 58

continuous variation

Answer 58

continuous variation results in a range of phenotypes between two extremes; examples include height and weight

Question 59

discontinuous variation

Answer 59

discontinuous variation results in a limited number of phenotypes with no intermediates; examples include ABO blood groups, seed shape in peas and seed colour in peas

Question 60

human skin colour is what kind of variation

Answer 60

continuous distribution

Question 61

human skin colour may be influenced by

Answer 61

environmental factors

Question 62

characteristics are controlled by what

Answer 62

polygenes and show continuous variation

Question 63

normal distribution curve

Answer 63

show variability but with value grouped symmetrically around a central value

Question 64

skewed distribution

Answer 64

values reduce in frequency more rapidly on one side of the most frequently obtained value than on the other

Question 65

what do box and whisker plots show

Answer 65

differences in the mean and range