Ch 19

Question 1

Prokaryotic DNA

Answer 1

DNA is “naked” not complexed with proteins; negative charges neutralized by calcium ions; short circle of DNA; only 3,000 genes; few introns and mRNA processing is simple

Question 2

Eukaryotic DNA

Answer 2

has nucleosome histones and forms chromosomes; each DNA molecule is long and can carry thousands of genes; contains introns and large segments of DNA do not code for any type of RNA

Question 3

Organelles

Answer 3

prokaryotes lack membrane bound organelles; only have ribosomes and storage granules in their cytoplasm; eukaryotes have nuclei and mitochondria and plants and algae have plastids

Question 4

Endosymbiont theory

Answer 4

the theory that plastids and mitochondria arose as prokaryotes that were living symbiotically within an early eukaryotic cell; prokaryotes evolved to the level of having a membrane-bound nucleus

Question 5

Origin of Mitochondria

Answer 5

the early eukaryotes engulfed but did not digest a prokaryote, which then evolved into a mitochondrion

Question 6

Origin of Plastids

Answer 6

some descendants of that early eukaryote would engulf but not digest a prochlorophyte type of cyanobacterium, which would evolve into a plastid

Question 7

Spore (n)

Answer 7

a single cell that is a means of asexual reproduction; it can grow into a new organism but cannot fuse like a gamete

Question 8

Gametophyte (n)

Answer 8

a haploid plant that produces gametes

Question 9

Fertilization (n + n -> 2n)

Answer 9

fusion of two gametes (egg and sperm)

Question 10

Zygote

Answer 10

the diploid cell formed as the result of the fusion of two gametes

Question 11

Sporophyte (2n)

Answer 11

a diploid plant that produces spores

Question 12

Sporangium (2n)

Answer 12

a structure that produces spores

Question 13

Meiosis (2n -> n+n)

Answer 13

reduction division; a process in which nuclear chromosomes are duplicated once but divided twice; chromosome number is reduced; becomes independent chromosomes