Lecture 15: From Genotype to Phenotype

Question 1

What do genes encode?

Answer 1

proteins that produce a diverse range of traits

Question 2

Gene

Answer 2

basic unit of genetic
information. Genes determine the
inherited characters

Question 3

Genome

Answer 3

the collection of
genetic information

Question 4

chromosomes

Answer 4

storage units of
genes

Question 5

DNA

Answer 5

nucleic acid that
contains the genetic instructions
specifying the biological
development of all cellular forms
of life

Question 6

locus

Answer 6

location of a gene/marker on the chromosome

Question 7

Allele

Answer 7

alternative form of a gene, each parent donates 1 allele for every gene

Question 8

Homozygous alleles

Answer 8

identical to each other; both letters are the same

Question 9

Heterozygous alleles

Answer 9

different from each other, letters are different,

Question 10

most human cells contain

Answer 10

46 chromosomes: 2 sex chromosomes (X, Y) and 22 pairs of autosomes

Question 11

phenotype

Answer 11

expression of a genotype

Question 12

Dominant allele

Answer 12

expressed even if it is paired with a recessive allele

Question 13

Recessive allele

Answer 13

only visible when paired with another recessive allele

Question 14

central dogma

Answer 14

DNA –> mRNA –> Protein

Question 15

Replication

Answer 15

DNA –> DNA, occurs in nucleus

Question 16

Transcription

Answer 16

DNA –> mRNA, occurs in nucleus

Question 17

Translation

Answer 17

mRNA –> Protein, occurs in ribosome in cytoplasm

Question 18

Qualities of DNA

Answer 18

nucleus only, double stranded, ATCG, deoxyribose sugar

Question 19

Qualities of RNA

Answer 19

nucleus and cytoplasm(ribosome), single stranded, AUCG, ribose sugar

Question 20

Main types of RNA (3)

Answer 20

mRNA - messenger
tRNA - transfer
rRNA - ribosomal

Question 21

steps of transcription

Answer 21

DNA –> pre-mRNA –> RNA; all occurs in nucleus

Question 22

Initiation

Answer 22

RNA polymerase binds to DNA at promoter region

Question 23

Promoter

Answer 23

before gene that is to be transcribed, determines which strand of DNA to use

Question 24

Elongation

Answer 24

adds nucleotides to mRNA strand based on DNA strand in 5’ –> 3’ direction

Question 25

Termination

Answer 25

RNA polymerase “falls off” the DNA strand when termination seq. (terminator) is reached

Question 26

RNA processing

Answer 26

pre-mRNA –> RNA

Question 27

5’ cap

Answer 27

guanine and phosphate cap on 5’ end of mRNA

Question 28

3’ poly-A tail

Answer 28

50 to 250 Adenines are added to the 3’ end of the mRNA

Question 29

introns

Answer 29

non-coding sections of mRNA, don’t leave the nucleus – only on pre-mRNA

Question 30

Exons

Answer 30

coding sections (expressed) of
mRNA, Exit the nucleus – final mRNA

Question 31

snRNPs

Answer 31

cut the introns

Question 32

Ribozyme

Answer 32

RNA that functions like an enzyme

Question 33

Spliceosomes

Answer 33

join remaining exons together to form final mRNA

Question 34

protein folding structures

Answer 34

primary, secondary, tertiary, quaternary (multiple subunits)

Question 35

role of chaperone proteins

Answer 35

assist in protein folding

Question 36

signal peptide

Answer 36

directs proteins through endomembrane system

Question 37

epigenetics

Answer 37

the study of stable changes in gene function that do not involve alterations in the DNA sequence

Question 38

epigenetic changes

Answer 38

DNA methylation and histone modification, each of which alters how genes are expressed without altering the underlying DNA sequence

reversible and do NOT change DNA seq., but can change how body reads DNA seq.