Cell reproduction and the Continuity of Life: Sexual reproduction methods Flashcards
Test review
What is the sexual life cycle of humans?
-Males produce sperms and females produce eggs
-Sperm fertilizes egg (Zygote)
-Zygote develops into a baby
-Female gives birth
What are the two stages of moss in alteration of generations?
-Haploid (n) Gametophyte
-Diploid (2n) Sporophyte
The male and female plants (Gametophytes) are separate.
What happens with moss in alteration of generations?
-Male gametophytes release sperm
-Sperm swims through water into the female gametophyte’s egg (external fertilization)
-The zygote (sporophyte) grows from the top of the female plant, and reproduces asexually via spores
What is unique about alteration of generations with Jellyfish?
They alternate between a sexual and asexual reproduction stage throughout their life.
What is the order of alteration of generations with jellyfish?
Jellyfish -> Egg + Sperm -> Zygote -> Blastula -> Larva -> Larva Settles (Into the ground) -> Becomes a polyp -> Polyp produces jellyfish asexually -> Jellyfish matures
What happens in sexual conjugation?
2 bacteria become linked together via a pilus, and one of them transfer all or some of its chromosomes to the other. The receiving cell then divides via binary fission with new genetic material.
What are the parts of the stamen? (Male reproductive organ in a flowering plant)
Anther - Where pollen is produced and stored
Pollen - Cases that contain male gametes
Filament stalk - Supports the anther
What are the parts of the pistil? (Female reproductive organ in a flowering plant)
Stigma - Sticky “lip” of the carpel that captures pollen grains
Style - Stalk that supports the stigma
Ovary - Swollen base of the carpel that contains ovules
Ovules - Sacs that contain female gametes
How does angiosperm fertilization (Double fertilization) occur?
Pollination from wind or insects brings pollen from the plant’s male parts to it’s female parts, where it forms into sperm and a pollen tube. The tube brings the sperm to the egg cells located inside the ovules within the ovary.
What are the two nuclei that each pollen grain has and what does each do?
Tube nucleus - Digs a pollen tube down through the style and into the ovule
Generative nucleus - Forms two sperm, one of which fertilizes the 2n endosperm into a 3n endosperm that becomes food for the embryo, whilst the other fertilizes an egg to make a zygote
What happens to the ovary and ovule in angiosperm fertilization (double fertilization)?
Ovule - Forms a seed coat for the zygote to grow into an embryo within
Ovary - Becomes the fruit. May dry up to form a hard shell (Peanuts) or may remain fleshy (Apples).
What are bacteriophages?
A virus that is known to target bacteria. They have both lytic and lysogenic cycles, which are neither sexual or asexual as the virus uses it’s hosts metabolic machinery to produce more viruses.
What happens in the lysogenic cycle?
Phage DNA is incorporated into the host’s genome where it passes down generationally. Stressful conditions (Sickness, starvation, chemical exposure) may cause the phage to excise from host DNA and enter the lytic cycle.
What happens in the lytic cycle?
The phage replicates and lyses the host cell, spreading phages all over.
What is a prophage?
Host cell genomes that have had phage DNA incorporated into them.
