Genetics

Question 1

Genes

Answer 1

unit of genetic material, a defined portion of chromosomes that encodes for a particular trait or substance such as hair color, blood type, etc.

Question 2

Alleles

Answer 2

the different forms a particular gene can occur in (brown, green, blue)- you have two copies of each gene (one from mom and one from dad) so there are two potential alleles for each

Question 3

homozygous

Answer 3

2 identical alleles for a particular gene

Question 4

heterozygous

Answer 4

2 different alleles for a particular gene

Question 5

Dominance

Answer 5

will always be expressed, indicated by a capital letter

Question 6

Recessive

Answer 6

will be masked by a dominant gene, can only be expressed if there is no dominant gene present- indicated by a lower case letter

Question 7

Codominant

Incomplete dominant

Answer 7

neither masks the other so both are expressed (AB blood type)
Incomplete dominance- the traits blend (pink, RW, RR red, WW, white)

Question 8

Genotype

Answer 8

the makeup of the genes, which 2 alleles are present

Question 9

phenotype

Answer 9

what actually gets expressed-what you “see”

Question 10

Monohybrid cross of dominant or recessive traits
mom brown eyes-Bb
dad blue eyes-bb

mom brown eyes-Bb
dad brown eyes-Bb

Answer 10

50% blue eyes (bb)
50% brown eyes (Bb)

75% brown eyes- BB or Bb
25% blue eyes- bb

Question 11

dihybrid cross

Answer 11

two traits, four results or phenotypes will be seen

Question 12

Blood Types

Answer 12

are based on what is on the cell surface
Type A- A antigen on red blood cell’s (RBCs) surface
Type B- B antigen on the surface
Type AB- both A and B antigens on the surface
Type O- neither A or B antigen on the surface

Question 13

genetics of blood types

Answer 13

O is recessive, must be homozygous (OO)
A is dominant, can be AA or AO
B is dominant, can be BB or BO
AB is codominant

Question 14

Blood Donation/transfusion

Answer 14

Type A-makes antibodies against B, can receive from A or O
Type B- makes antibodies against A, can receive from B or O
Type AB- can receive from everyone (A, B, or O)
Type O- makes antibodies against A and B, can only receive from O, but is a universal donor

Question 15

Rh disease
Rh+ is dominant
Rh- is recessive

Answer 15

a situation where Rh- mother is carrying an Rh+ child. After she is exposed to Rh+ RBCs during the first pregnancy, she may produce IgG antibodies which will cross the placenta and attack fetal RBCs in later pregnancies

hemolytic disease of the newborn

Question 16

X chromosomes disease

Answer 16

generally affects males since they only have on X chromosome, the second X chromosome is always a good back up for females

Hemophilia- x-linked disorder, recessive, defect in blood clotting protein
Color blindness

Question 17

Autosomal Recessive disorders

Answer 17

2 copies of the bad gene in order for it to be expressed 
Albinism
Sickle cell anemia
PKU
Cystic fibrosis

Question 18

Albinism

Answer 18

a defect in the production of melanin

Question 19

Sickle Cell Anemia

Answer 19

single amino acid change in the gene that makes hemoglobin, RBCs have sickle shape

Question 20

PKU

Answer 20

Phenylketonuria-enzyme defects leads to the build-up of phenylalanine in the bloodstream and neurological problems

Question 21

cystic fibrosis

Answer 21

enzyme defect causes the production of abnormal mucus that cause problems in the respiratory and gastrointestinal tract

Question 22

Chromosomal and structural disorders

Answer 22

physical or structural defects in the chromosomes rather than in the genes, often from nondisjunction- where one or more chromosomes pairs do not separate during mitosis or meiosis

Trisomy/Polyplodiys- an unusual amount of a particular chromosome
Ex: down syndrome (aka trisomy 21), XXY or XYY extra copy of a chromosome
Monosomy/anuplodiy- one copy of a chromosome, just an X, example: Turner’s syndrome

Question 23

Replication fork

Answer 23

the initial step is the splitting the two strands to form a replication fork- it involves the helicase enzymes

Question 24

DNA polymerase-

Answer 24

synthesis the DNA complementary strand

Question 25

Ligase

Answer 25

joins the gaps in the lagging DNA strands

Question 26

transcription

Answer 26

One strand of DNA molecule is read to reproduce messenger RNA (mRNA)

Question 27

Translation

Answer 27

The mRNA attaches to ribosomes to trigger the production of protein- the codons in the mRNA are “read” by transfer RNA (tRNA) to place the appropriate amino acids in their place

Question 28

Promoters

Answer 28

The DNA sequence that triggers gene expression and transcription

Question 29

Repressors

Answer 29

which block gene expression

Question 30

Operons

Answer 30

a cluster of genes controlled by a single promoter

Question 31

Mutation

Answer 31

a permanent change in the structure of the DNA, which is passed on to the offspring of the effected cells, may or may not be noticeable or harmful

Source= radiation and chemical…virusus can cause mutaitons also

Question 32

Missense

Answer 32

a single base is changed- leads to a change in the codon (UGC to UGG), which in turn leads to the production of a different amino acid, the “sense” or meaning of the codon has been changed
A change in the first two of the three letters in a codon has the grates impact

Question 33

Nonsense

Answer 33

single base change- leads to a change in the codon so that it becomes a stop codon which terminates the synthesis of the protein at that point the mRNA instead of at the real of the protein

Location of the stop codon determines its impact

Question 34

Frame-shift

Answer 34

The way the codons in the mRNA are read is messed up by adding or removing bases (location determines impact)

insertion- extra base is inserted into the DNA molecule - this throws off the codon it ends up in all those ‘downstream’ from the point (major change)

deletion- base is delated “downstream” major change

Question 35

Recombination

Answer 35

transfer of genetic information from one organism to another
donor to recipient

Question 36

Transformation

Answer 36

DNA from a dead bacteria which is broken apart is taken up through the cell wall of the recipient bacteria and integrated into its own DNA

Question 37

Conjugation

Answer 37

involves the exchange of a small piece of DNA (a plasmid) or possible chromosomal DNA from one bacteria to another-the bacteria are joined by a tube known as sex pilus

Question 38

Transduction

Answer 38

a virus (bacteriophage) carries genetic info from one bacteria to another

Question 39

Transposons

Answer 39

transposable genetic elements - also known as “jumping genes” - genetic elements that move from one pace to another within a chromosome