Reproduction Notes

codon

three nucleotides that code for amino acid

chromosome

continuous strand of DNA

homologous chromosome

chromosomes with the same genes but different alleles

genome

entire genetic makeup of an organism

gene

basic unit of inheritance, point on a chromosome

Asexual reproduction

one parent, identical offspring.

types of asexual reproduction

binary fission - prokaryotes
mitosis - eukaryotes
- budding- kid grows off adult
- fragmentation- part of parent falls off and becomes kid

sexual reproduction

two parents, different offspring
- bacterial conjugation- prokaryotes and their plasmids (not exactly sexual reproduction but its the closest thing prokaryotes have)
- meiosis + fertilization - eukaryotes

why reproduce sexually?

sexual reproduction increases genetic diversity, bad mutations in asexual reproductions will inherit all bad mutations (which are more likely).
sexual reproduction can produce unique combos that are better than what the parents had.

nucleotide

monomer of DNA

allele

variant of a gene

trait

a physical characteristic of an organism, may be the result of genes and alleles

allosomes

sex chromosomes (mammals- x and y) (reptiles- z and w)
some animals don't have sex chromosomes.

autosomes

non-sex chromosomes

why is everything in pairs?

for sexual reproduction

haploid

having one set of chromosomes

diploid

having two sets of chromosomes

basic of reproduction

haploid gametes (sperm and egg) fuse to for a diploid zygote (fertilized egg)

polyploid

having more than two sets of chromosomes
triploid- 3
tetraploid- 4
pentaploid -5
hexaploid- 6
polyploidy is rare but very common in plants.
only even numbered sets are fertile

animals sexual life cycle

mitosis : 2N-->2N
Meiosis- 2N-->N (makes gametes)
animals have the simplest sex cycle (uncommon too)

plant sexual life cycle

- original cycle animals modified to get theirs
mitosis- 2N->2N or 1N-->1N
meiosis- 2N-->1N
gametes created through mitosis
meiosis creates spores
plants display alternation of generations

what can mosses tell us about evolution?

The diploid stalk is just a gene mixer. Diploids og role is just for reprouction.

Pollen

a gametophyte that produced the sperm.