Genetics

Question 1

Define genome

Answer 1

The sum of all DNA

Question 2

Explain the genetic code

Answer 2

• Rules that translate the nucleotide sequence into amino acid sequence - plants make 20 aa sequences
• Based on 3 nucleotides/codons
• Code is universal and is used for bacteria, protists, fungi, plants, and animals

Question 3

The difference between plant genome and and human genome

Answer 3

Plants:
- plastids (produce and store food, and controls pigments of cell) contain dna
- most are polyploid (more than 2 complete chromosomes)
- coding and non-coding sequences evolve faster

Humans:
- have >20,000 genes with >98% noncoding dna

Question 4

Explain Gregor Mendel

Answer 4

• creates the field of genetics
• rejected the idea of blending inheritance and that genetic is a fluid that mixes

Question 5

Monohybrid vs dihybrid cross

Answer 5

Monohybrid cross: parents differ in the alleles for one gene

Dihybrid cross: parents differ in the alleles for 2 genes

Question 6

What’s a punnett square?

Answer 6

A diagram used to predict the genotypes of a particular cross

Question 7

Explain the “law of independent assortment”

Answer 7

The outcome of a dihybrid cross - two traits are passed to offspring independently of each other

Question 8

Why does the law of independence not always apply?

Answer 8

1. dominance may not be incomplete
2. many traits are determined by more than one gene
3. environment can modify gene expression
4. many traits are quantitative

Question 9

Timeline: 1858

Answer 9

Darwin’s theory of evolution

Question 10

Timeline: 1866

Answer 10

Mendel publishes his work

Question 11

Timeline: 1953

Answer 11

Watson and Crick provided DNA model

Question 12

Timeline: 1961

Answer 12

Nirenberg cracks genetic code

Question 13

Timeline: 2003

Answer 13

Human genome sequenced

Question 14

What do breeders look at?

Answer 14

Quantitative traits: yield, disease resistance, and stress tolerance (drought and force)

Question 15

What are some ways to modify plants?

Answer 15

• traditional breeding
• transgenic planting
• genom editing

Question 16

Explain plant breeding

Answer 16

• accelerated evolution guided by humans rather than nature
• using the gene of “good plants” increase representation in future generations, but also risky
• a type of natural variation within a population
• can help create disease resisting plants

Question 17

What are gene banks?

Answer 17

Drying seeds and freezing plant parts preserve agricultural diversity

Question 18

Explain transgenic plants

Answer 18

• inserting genes from any organism into plants
• a way to create resistance to insects and herbicides (thanks to universal genetic code)

Question 19

Transgenic plants vs transgenes

Answer 19

Transgenic plants: plants that include foreign genes

Transgenes: genes that are inserted into plants