7C- genotype and phenotype

Question 1

diploid

Answer 1

having two sets 2n of each chromosome, one from each parent

Question 2

homozygous

Answer 2

having identical alleles for the same gene on homologous chromosomes

Question 3

heterozygous

Answer 3

having different alleles for the same gene on homologous chromosomes

Question 4

dominant allele

Answer 4

the variant of a gene that masks the effect of a recessive allele on the same gene on a homologous chromosome

Question 5

recessive allele

Answer 5

the variant of a gene that is masked by a dominant allele on a homologous chromosome

Question 6

complete dominance

Answer 6

a pattern of dominance where only the dominant allele from the genotype of a heterozygous individual is expressed in the phenotype of that organism

Question 7

phenotype

Answer 7

the physical or biochemical characteristics of an organism that are the result of gene expression (set of genes) and the environment

Question 8

carrier

Answer 8

an organism that has inherited a copy of a recessive allele for a genetic trait but doesn’t display the trait due to it being masked by the presence of a dominant allele

Question 9

genotype

Answer 9

the genetic composition of an organism at one particular gene locus, as represented using letter symbols

Question 10

codominance

Answer 10

a pattern of dominance where both alleles from the genotype of a heterozygous individual are dominant and expressed in the phenotype of that organism

Question 11

incomplete dominance

Answer 11

a pattern of dominance where neither allele from the genotype of a heterozygous individual is dominant and both are expressed in an intermediate phenotype

Question 12

sex linked genes

Answer 12

genes that are located on a sex chromosome

Question 13

x linked traits

Answer 13

a trait controlled by a gene that is located on the x chromosome

Question 14

y-linked traits

Answer 14

a trait controlled by a gene that is located on the y chromosome

Question 15

how many alleles do we inherit?

Answer 15

every diploid organism inherits a particular combination of two alleles from their parents

Question 16

contrast homozygous and heterozygous cells?

Answer 16

in homozygous cells, an individual inherits two identical alleles from each parent whether its two dominant or two recessive.

Question 17

contrast dominant and recessive alleles

Answer 17

a dominant allele is the stronger form of a pair of alleles and is represented with a capital letter. it will always be expressed (AA or Aa)
a recessive allele is the weaker form of a pair of alleles and is represented with a lowercase letter. can only occur if homozygous recessive

Question 18

what occurs in heterozygous individuals?

Answer 18

complete dominance- a pattern of dominance where only the dominant allele from the genotype of a heterozygous individual is expressed in the phenotype of that organism

Question 19

contrast genotypes and phenotypes

Answer 19

phenotypes are the physical/biochemical characteristics that are the result of gene expression and the environment
genotypes are the genetic composition of an organism at one particular gene locus, as represented using letter symbols

Question 20

what is it called when there is a recessive allele in a heterozygous individual

Answer 20

although a dominant allele may mask the recessive allele, a person who is heterozygous at a specific gene locus is still a carrier→ can pass on the recessive allele to their offspring despite not displaying the trait

Question 21

are dominant alleles more common than recessive?

Answer 21

no, for example the dominant trait is dwarfism

Question 22

create a zygosity table- general table

Answer 22

zygosity | genotype
homo dom | AA
hetero | Aa
homo rec | aa

Question 23

what is phenotype influenced by

Answer 23

genotype and the environment, making it susceptible to change over time

Question 24

contrast codominance and incomplete dominance

Answer 24

codominance is when both alleles from the genotype are fully expressed in the phenotype of a heterozygote ( both are dominant and neither mask)
incomplete dominance is when neither allele is fully expressed in the phenotype of a genotype (blending of both alleles)

Question 25

give an example of codominance

Answer 25

both red and white petals in a heterozygote

Question 26

give an example of incomplete dominance

Answer 26

heterozygotes would display a mix of red and white forming pink

Question 27

zygosity of codominance and incomplete dominance

Answer 27

homo option A- CACA
hetero- CACB
homo option B- CBCB

Question 28

contrast x linked and y linked traits

Answer 28

X-linked traits a trait controlled by a gene that is located on the X chromosome- more likely to be found in males as they only have one X and will be expressed regardless. but can only be passed down to daughters
Y-linked traits a trait controlled by a gene that is located on the Y chromosome- thus only impacting males

Question 29

genotypic variations for colour blindness

Answer 29

affected female- XbXb
unaffected female (carrier)- XBXb
unaffected female- XBXB
affected male- XbY
unaffected male XBY

Question 30

why is colour blindness more common in men

Answer 30

because males only have one X chromosome, if they inherit the faulty gene that codes for colour blindness they will be colour blind. this is because they only have one X chromosome. lower chance for women