Inheritance

Question 1

in summary what did Mendel observe

Answer 1

true-breeding pea plants
produced genetically identical offspring
tall produced tall and short produced short
true breeding plants self pollinate

Question 2

what are menders 3 laws

Answer 2

law of segregation
law of independent assortment
principle of dominance

Question 3

law of segregation

Answer 3

yeah individual possesses two units of inheritance for each characteristic
although only one of These is transmitted to each offspring

Question 4

law of independent assortment

Answer 4

genes at different loci segregate independently

Question 5

principle of dominance

Answer 5

in pairs of alleles that are different
one allele will mask the effect of the other allele

Question 6

human traits to show mendelian inheritance

Answer 6

hitchhikers thumb
tongue rolling
attached earlobes

Question 7

human earwax

Answer 7

consistency of earwax
SNP in ABCC11 gene is the determinant of human earwax type

Question 8

mendelian genetics in inherited diseases

Answer 8

sickle cell disease
huntingtons

Question 9

different ways genetic condition can be inherited

Answer 9

mutations in single gene and usually inherited in one of several patterns

Question 10

autosomal dominant

Answer 10

one mutated copy of gene is sufficient for person to be affected by disorder
can inherit from affected parent

Question 11

huntington disease and Marfan syndrome inheritance

Answer 11

may result from new mutation in gene and our in people with no history of disorder

Question 12

loci are on an autosome

Answer 12

not X or Y chromosome

Question 13

dominance being relative based

Answer 13

on the function of the protein and nature of the allele

Question 14

incomplete dominance

Answer 14

where allele has partial effect over other allele

Question 15

co-dominance

Answer 15

where both alleles are apparent

Question 16

Huntingdons disease

Answer 16

neurodegenerative disorder caused by an allele that codes for a dominant phenotype
offspring have 50% chance of inheriting allele and therefore disease from a parent with the disease

Question 17

autosomal reessive

Answer 17

both copies of the gene in each cell have mutations
parents of individual with autosomal recessive condition each carry one copy of the mutated gene but they typically don’t show signs or symptoms
typically not seen in every generation in a family

Question 18

examples of autosomal recessive conditions

Answer 18

cystic fibrosis
sickle cell

Question 19

sickle cell disease

Answer 19

blood disorder
RBCs distorted into sickle or crescent shape leading to premature breakdown or getting stuck in small blood vessels leading to anaemia
autosomal recessive

Question 20

heterozygous carriers of sickle cell disease

Answer 20

express partial phenotype
some blood cells are normal and some distorted
only sometimes have moderate symptoms

Question 21

full sickle cell disease

Answer 21

individual must have 2 copies of alleles coding or recessive phenotype
must be homozygous recessive

Question 22

x linked dominant

Answer 22

loci are on X chromosome
allele masks other allele on other chromosome

Question 23

x linked dominant in males vs females

Answer 23

males only require one copy of the gene to cause the disorder, often more severe
females require one of the two copies is sufficient

Question 24

x linked recessive

Answer 24

XX females allele is masked by other allele on other chromosome unless both alleles are mutant
XX female has one normal and one mutant
doesn’t normally show any phenotype
XY males always affected

Question 25

X- linked recessive disorders

Answer 25

one altered copy of gene in each cell is sufficient in males
in females mutation must occur in both copies of gene

Question 26

example of x linked recessive disorders

Answer 26

haemophilia
fabry disease

Question 27

fabry disease

Answer 27

inherited disorder that can affect many parts of the body
espeially heart and kidneys
have problems breaking down globotriaosylceramide (GL-3)
belongs to group of disorders known as lysosomal storage disorders

Question 28

Y linked

Answer 28

XY males always affected
not many known conditions
200 genes on Y chromosome
only passed father to son

Question 29

Y chromosome infertility

Answer 29

de novo mutations
caused by whole gene deletions in AZF region of Y chromosome responsible for sperm production

Question 30

non-mendelian inheritance

Answer 30

where both alleles are expressed and influence the trait or genetic disease

Question 31

ABO blood system

Answer 31

blood groups result from inheritance of alleles within a gene that can modify protein on red cells
3 alleles are ABO
O silent, A and B make different carbohydrate modifications
if they can’t make A or B then possess natural IgM antibodies against A and B proteins
major concern in blood transfusion

Question 32

mitochondrial linked

Answer 32

loci are in mitochondrial DNA
distinct from mutations in nuclear DNA that affect mitochondria
passed mother to children exclusively

Question 33

what is heritability

Answer 33

measure of how well differences in peoples genes account for differences in their traits

Question 34

heritability as a statistical concept

Answer 34

h^2
describes how much of the variation in a given trait can be attributed to genetic variation
estimate of the heritability of a trait is specific to one population in one environment
can change as circumstances change

Question 35

what do heritability estimates range from

Answer 35

0 to 1
0 indicates almost all variability is due to environmental factors, very little genetic difference influence

Question 36

characteristics with heritability of 0

Answer 36

religion
language spoken
political preference
not under genetic control

Question 37

phenylketonuria (PKU)

Answer 37

high heritability and most complex traits in people
including intelligence, multifactorial diseases
variability due to combination of genetic and environmental factors

Question 38

despite knowing the heritability what do you not know

Answer 38

which genes or environmental influences are involved
or that if it is 0.7 doesn’t mean that 70% are caused by genetic factors its 70% of variability in trait is due to genetic differences

Question 39

polygenic

Answer 39

combined affect of multiple genes

Question 40

polygenic

Answer 40

combined affect of multiple genes

Question 41

what are many health conditions caused by

Answer 41

polygenic
interactions between genes and environment

Question 42

exampels of diseases caused by multiple genes/ gene environment

Answer 42

heart disease
type 2 diabetes
schizophrenia
certain cancers

Question 43

label the image

Answer 43

Question 44

label green pink and blue

Answer 44

green is homologous pair, homologs
diploid
pink= maternal homolog
blue= paternal homolog

Question 45

what does each diploid human cell nucleus contain

Answer 45

2 similar versions of each autosome plus pair of sex chromosomes
46 chromosomes
maternal and paternal homologs/ homologous chromosomes

Question 46

sexual reproduction is result of what

Answer 46

fusion of two gametes
including genetic material
need mechanism by which genetic material of precursor cell (gametes) is reduced by a half
meiosis

Question 47

cell cycle and mitosis

Answer 47

Interphase: cellular components are replicated
G1 and G2: cell duplicates specific molecules and structures
S phase: cell replicates DNA
Mitosis: cell distributes its contents into two daughter cells
Interphase: chromosomes are uncondensed
Prophase: the spindle condenses, centrioles appear and the nuclear envelope breaks down
Metaphase: chromosomes align
Anaphase: centromeres and chromatids part
Telophase: spindle disassembles and nuclear envelope reforms
Two identical diploid daughter cells (2n)

Question 48

meiosis 1 and 2

Answer 48

Prophase I (early): synapsis and crossing over occurs
Prophase I (late): chromosomes condense, become visible; spindle forms; nuclear envelope fragments; spindle fibres attach to chromosomes
Metaphase I: paired homologous chromosomes align across equator of cell
Anaphase I: homologous chromosomes separate to opposite poles of the cell
Telophase I: nuclear envelope partially assembles around chromosomes; spindle disappears, cytokinesis divides cell in two
Prophase II: nuclear envelope fragments; spindleforms and fibres attach to both chromosomes
Metaphase II: chromosomes align across equator of cell
Anaphase II: sister chromatids separate to opposite poles of the cell
Telophase II: nuclear envelopes assemble around two daughter nuclei; chromosomes decondense; spindle dissappears
Four identical haploid daughter cells (1n)

Question 49

How do genetic differences arise

Answer 49

Independent assortment
Chiasmata

Question 50

haploid cell variations

Answer 50

independent assortment and chiasmata

Question 51

independent assortment

Answer 51

yeah haploid cell contains one chromosome from each of the homologous pairs
maternal and paternal chromosomes are shuffled into novel combinations

Question 52

chiasmata

Answer 52

crossing over
homologous maternal and paternal chromosomes exchange genetic information during prophase 1

Question 53

are chromosomal disorders inherited

Answer 53

most aren’t such as Down syndrome and Turner syndrome
some are caused by changed in the number of chromosomes and not inherited but occur as random events

Question 54

turner syndrom

Answer 54

genetic condition where instead of individual being 46 XX they are 45 XO
single X chromosome
meiotic disjunction is most often cause of chromosomal loss
can be mosaic where not all cells have lost X chromosome