Lecture 20: Genetics and Plant Breeding - 11/18

Question 1

Nucleus

Answer 1

A structure that contains a cell’s genetic information

Question 2

How is DNA stored (how many nucleotides in each group)?

Answer 2

DNA is stored as a linear sequence in groups of 3

Question 3

What are the 4 base pairs?

Answer 3

Adenine (A), guanine (G), cytosine (C), guanine (G)

Uracil (U)

Question 4

Uracil

Answer 4

Replaces thymine in RNA

Question 5

How are nucleotide bases paired?

Answer 5

A is paired with T (or U in RNA)
G is paired with C

Question 6

Which pentose sugars do DNA and RNA have?

Answer 6

DNA has deoxuyribose
RNA has ribose

Question 7

Chromosomes

Answer 7

In the nucleus, subgroups of DNA that are tightly packed with histones (proteins)

Question 8

Diploid

Answer 8

Has two pairs of chromosomes

Question 9

What regions is the DNA sequence made up of?

Answer 9

It is made up of genes and intergenic regions (regions in between genes)

Question 10

Exons

Answer 10

Portions of the gene that will be transcribed to mRNA and then to protein

Question 11

Introns

Answer 11

Portions of the gene that will not be translated (will be spliced out)

Question 12

Central dogma

Answer 12

Information flows from DNA–>RNA–>protein

Question 13

What is the process of turning DNA to RNA called?

Answer 13

Transcription

Question 14

What is the process of turning RNA to protein called?

Answer 14

Translation

Question 15

Where is mRNA synthesized?

Answer 15

The nucleus

Question 16

Once mRNA has been synthesized, where does it travel?

Answer 16

It exits the nucleus through its nuclear pores, where translation then occurs on ribosomes in the cytoplasm or rough ER (endoplasmic reticulum)

Question 17

What are the three types of RNA?

Answer 17

mRNA, rRNA, tRNA

Question 18

mRNA

Answer 18

Messenger RNA. Contains the codon (3 pase pair) information to build a protein

Question 19

rRNA

Answer 19

Ribosomal RNA. Assembles with ribosomal proteins to form the ribosome, which is where mRNA is read and translated to protein form

Question 20

tRNA

Answer 20

Transfer RNA. Carries amino acids to ribosomes to make proteins. Has an anticodon, which is the matching base pairs to the codon

An example of an anticodon for AUG is UAC because A matches with U, U matches with A, and G matches with C

Question 21

Mitosis - # of chromosome duplications and nuclear/cellular divisions

Answer 21

One chromosome duplication
One nuclear/cellular division

Question 22

Meiosis - # of chromosome duplications and nuclear/cellular divisions

Answer 22

One chromosome duplication
Two nuclear/cellular divisions

Question 23

What is the difference between genotype and phenotype?

Answer 23

Genotype is the genetic makeup of an organism, whereas phenotype is its appearance/traits

Question 24

How might genotype and phenotype for plants be similar yet different?

Answer 24

It’s possible for genotypically different plants to look phenotypically similar, and phenotypically different plants to be genotypically similar

Question 25

Allele

Answer 25

A version of a gene. Diploid organisms have two alleles for one gene

Question 26

Homozygous

Answer 26

Possessing two alleles of the same type

Question 27

Heterozygous

Answer 27

Possessing two alleles of different types

Question 28

How can phenotype be deceiving in regards to genotype?

Answer 28

A homozygous and heterozygous genotype can produce the same phenotype

Question 29

Is there complete independent assortment of genes? Why or why not?

Answer 29

No, because genes reside on chromosomes, which are rearranged during meiosis (not the genes themselves)

Question 30

Crossing over

Answer 30

In meiosis, when two homologous chromosomes cross over at a chiasma, exchanging genetic information

Question 31

Linked genes

Answer 31

When two genes are on the same chromosome

Question 32

Mutations

Answer 32

Changes in DNA sequence, which are normally harmful (but occasionally beneficial)

Question 33

Do all mutations result in a change?

Answer 33

No, because there is some redundancy in the genetic code; multiple combinations of nucleotides code for the same amino acid, so sometimes a mutation will still produce the same amino acid, producing no change