Introducing genomes

Question 1

what is a genome?

Answer 1

the sum total of all the DNA in an organism’s cells (a set of assembly instructions)

Question 2

what are the 2 types of eukayotic chromosomes?

Answer 2

• sex chromosomes
• autosomes

Question 3

what are prokarotic “chromosomes”?

Answer 3

typically circular, more gene-dense and much smaller

Question 4

what are eukarotic chromosomes?

Answer 4

• found in the nucleus of a cell
• The DNA inside the nucleus is organized into chromosomes.
• At the most basic level, a chromosome is a molecule of DNA that is tightly coiled around proteins called histones

Question 5

define karyotype

Answer 5

number of chromosomes in a cell

Question 6

define ploidy

Answer 6

the number of sets of chromosomes (2= diploid)

Question 7

define aneuploidy

Answer 7

wrong number of chromosomes

Question 8

what is the ploidy of wheat?

Answer 8

hexploid

Question 9

what is the ploidy of wild strawberries?

Answer 9

diploid

Question 10

what is the ploidy of cultivated strawberries?

Answer 10

octoploid

Question 11

what is the size of mitochondrial genomes?

Answer 11

~ 10-15kB

Question 12

what is the size of chloroplast genomes?

Answer 12

~ 100-200kB

Question 13

how are autosomal genes inherited?

Answer 13

• Autosomal dominant traits pass from one parent onto their child.
• Autosomal recessive traits pass from both parents onto their child.

Question 14

what are autosomal genes?

Answer 14

the gene in question is located on one of the numbered, or non-sex, chromosomes.

Question 15

who is mitochondrial eve?

Answer 15

All humans share a common direct maternal ancestor known as Mitochondrial Eve.

Question 16

what is the smallest known pathogen genome?

Answer 16

coconut cadang-cadang viroid
- a 246bp RNA molecule

Question 17

how are viral genomes compact?

Answer 17

genes in viruses often overlap or are multifunctional (polyprotein genes)

Question 18

how are prokaryotes genomes arranged?

Answer 18

• Generally compact, circular genomes
• Genes arranged into operons
• Plasmids as “optional extras”

Question 19

how are eukaryotes genomes arranged?

Answer 19

• Typically large genome (up to 150Gb; but Encephalitozoon cuniculi 2.9 MB )
• Organised into chromosomes (1 to 1600; usually 10-100)
• Organelles – mitochondria, plastids such as chloroplasts – can have genomes separate from the nuclear genome.

Question 20

what are metagenomes?

Answer 20

All the genes present in a whole ecosystem or environment

Question 21

how many base pairs are in the human genome?

Answer 21

just over 3 billion