Biology- Reproduction Flashcards
Cell division in unicellular organisms is a means of….
Reproduction.
Is it true that all cells in your body have the same chromosomes?
Yes. Except two sex chromosomes inside their nuclei which have half the number of chromosomes.
Cell division in multicellular organisms is a means of….
Growth, development and replacement of old cells.
Mitosis is…
Division of somatic cells DNA to it’s two daughter cells. Each daughter cell reci eves complete genome copy.
Nuclear division is called ……and precedes cell division which is called…..
Nuclear division: karyokinesis
Cell division: cytokinesis
List the 6 stages of mitosis.
Interphase Prophase Metaphase Anaphase Telophase Cytokinesis
What happens in interphase of mitosis?
90% of a cells life.
Each chromosome is replicated….chromosomes are two sister chromatid held together by centromere.
Cannot see individual chromosomes.
DNA is called chromatin(uncoiled).
Chromosome number within cell during mitosis/interphase is called….
Ploidy.
Somatic cells are diploid (2N).
2N comes from homologous pair of chromosomes made up of 2 sets of haploid (N) chromosomes from gamete cells.
What happens in Prophase of mitosis?
Chromosome condense….and spindles form. (Centrioles go toward opposite ends of cell. )
Nuclear membrane dissolves
What happens in Metaphase of Mitosis?
Chromosome align at the center of the cell and spindles attach to each chromatid at the centromere.
What happens in Anaphase of mitosis?
Sister chromatid split….spindles made of microtubules pull chromatids to opposing ends of cell.
What happens in Telophase of Mitosis?
Spindles dissolve and nuclear membranes form around each set of chromosomes. Chromosomes uncoil.
What happens in cytokinesis of mitosis?
Cytoplasm divides into two daughter cells. Each cell has complete nucleus and it’s own organelles
Cleavage furrow forms in animals.
Two differences between plant and animal cell division:
1) plants do not have centrioles…spindle is made by Microtubule organizing centers.
2) plants cannot form cleavage furrow….they separate via a cell plate.
How many cells are produced from meiosis?
Haploid (N). Half the number of chromosomes.
How many haploid cells are made in meiosis?
4 haploid cells- gametes.
Steps of meiosis.
Interphase. First division: prophase 1, metaphase 1, anaphase 1, telophase 1. Second division.
What happens in interphase of meiosis?
Parents cells chromosomes are replicated….4N chromosomes.
What is produced from the first meiotic division of meiosis?
Two intermediate daughter cells with 2N chromosomes with sister chromatids.
What happens in prophase 1 of meiosis?
Chromatin condenses into chromsomes, spindle appears and nuclear membrane disappear. Homologous chromosomes (one from each parent) pair up in synapsis. (Tetras is formed)
What are chiasmata?
Where chromatids in prophase 1 of meiosis line up and connect and break to exchange equivalent DNA pieces. CROSSING OVER.
Does crossing over happen to sister chromatids or homologous chromosomes?
Homologous chromosomes
What happens in metaphase 1 of meiosis?
Tetras align at equatorial plate and each homologous pair attaches via kinetichore to spindle fiber.
What happens in Anaphase 1 of meiosis?
Disjunction. Homologous pairs are pulled apart and go to opposite ends of cell. Random mixture of genes in each.
What happens in telophase 1 of meiosis?
Nuclear membrane forms around new nuclei. Each chromosome is still sister chromatids.
What is different about meiosis ii?
No chromosomal replication to start the process.
In females, only one daughter cells from meiosis becomes
A functional gamete.
3 things required for sexual reproduction:
1) functional gametes
2) union if sex cells (fertilization)
3) development of zygote to adult.
Male gonads are called:
Testes. They produce sperm.
Where does spermatogenesis occur?
Seminiferous tubules.
Females gonads are:
Ovaries. They produce oocytes.
What are hermaphrodites? 2 examples?
Both female and male gonads.
Hydra and earthworm.
What cells divide to make 4 haploid sperm?
Spermatagonia via meiosis.
Anatomy of sperm:
Head (nucleus and paternal genome)
Tail/flagellum propel the sperm
Neck has mitochondria for energy
Where dies oogenesis occur?
Ovaries.
How baby mature eggs are made from one diploid female sex cell?
1
What is a polar body?
Small cell from female meiotic division that degenerate.
Why is oogenesis different from spermatogenesis?
Oogenesis is discontinuous (limited number of eggs in prophase.)
Ploidy of zygote?
Diploid
What animals use external reproduction?
Fish and amphibians. Females lay eggs in water and males deposit their sperm.
Species that care for the young produce …….. Eggs.
Fewer.
Pathway of sperm:
Seminiferous tubules Epididymis Vas Deferens Ejaculatory duct N- Urethra Pen is
Where is testosterone made? What does testosterone regulate?
Testes. Secondary sex characteristics-hair, voice changes, etc.
Where are ovaries found?
Abdominal cavity below digestive system.
What is a follicle?
Multilayered sac of cells containing immature ovum.
Where is estrogen produced?
Follicle cells of ovaries.
Each month immature ovum is drawn into the…..
Fallopian tube (oviduct).
Each Fallopian tube opens into…
The uterus where fetus develops.
Lower, narrow end of uterus ……connects with the …..
Cervix connects with the vaginal canal.
What regulates the secretion of estrogen and progesterone?
LH and FSH which are regulated by GnRH.
What secretes estrogen?
Ovarian follicles and corpus luteum.
What does estrogen do?
Responsible for endometrium thickening and the development of the female reproductive tract. Secondary sex characteristics and sex drive.
When and where is progesterone secreted from?
Corpus luteum during the luteal phase of cycle.
What does progesterone do?
Development of endometrial wall for implantation of zygote.
4 stages of the menstrual cycle:
1) follicular phase
2) ovulation
3) luteal phase
4) menstruation
When does follicular phase begin?
Cessation of last cycle.
In follicular phase, hormone levels are lowest so negative feedback to hypothalamus are shut done which….
Allows the hypothalamus to release gonadotropin-releasing hormone.
What does the release of GnRH stimulate?
Release of FSH from anterior pituitary.
Where is FSH released from?
Anterior pituitary gland.
What does FSH do?
Stimulates follicle growth in the ovary.
What causes ovulation?
surge in LH levels/peak in estrogen levels.
LH (luteinizing hormone) induces the ruptured follicle to….
Develop into corpus luteum.
What does corpus luteum secrete?
Progesterone and estrogen.
If the ovum is not fertilized….
The corpus luteum atrophies.
When the corpus Leitrim atrophies there is a drop…
In progesterone and estrogen levels so the endometrium sloughs off….menstrual flow.
If fertilization occurs….
Placenta produces hCG (human chorionic gonadotropin).
What does hCG do?
Maintains corpus luteum.
How are plant life cycles represented?
Alternating between sporophytes and gametophytes.
Evolutionarily, has the sporophyte or gametophyte been dominant?
Sporophytes generation.
Gametophytes reproduce…..
Sporophytes reproduce….
Sexually (gametophytes)
Asexually (sporophytes)
What sexual stage is dominant for mosses?
Gametophyte.
Haploid gametophytes produce ……by mitosis.
Gametes
Diploid sporophytes produce ……by meiosis.
Haploid spore
What sexual stage is dominant for ferns?
Sporophytes. (Releases spores from the underside of leaves)
What are angiosperms?
Flowering plants.
What is the reproductive structure of an angiosperm?
The flower.
Pistils are …..
Stamens are….
Pistils are female
Stamens are male
Angiosperms have …..with cells that last for a short amount of time.
Gametophytes.
anatomy of a stamen
Filament and anther.
What does an anther produce?
Haploid spores that become pollen
Anatomy of pistil:
Stigma: sticky top to catch pollen
Style: tube that connects stigma to ovary
Ovary: enlarged based that contains ovules with eggs.
What do petals do?
Protect pistil. Attract insects for pollination.
What are sepals?
Green leaves that protect flower bud during development.
What is the male gametophyte in flower reproduction?
Pollen grain. Contains sperm nuclei when it divides on the stigma.
What is the female gametophyte in flower reproduction?
Embryo sac that contains nuclei
What makes the zygote in plant reproduction?
1 sperm nucleus
1 egg nucleus
What makes the endosperm?
1 sperm nucleus
2 polar nuclei
What does endosperm do?
Provides food for embryonic plant.
What is endosperm absorbed by?
Seed leaves (cotyledons).
How do prokaryotes reproduce?
Asexually.
4 types of asexual reproduction:
Fission, budding, regeneration, parthenogenesis.
What is binary fission?
DNA replicates and a new plasma membrane and cell wall grow inward.
What organisms undergo fission?
One-celled organisms:
Amoebae, paramecium, algae, bacteria
What is budding?
Replication of nucleus followed by unequal cytokinesis.
What organism experience budding?
Hydra and yeast.
What is regeneration?
Regrowth of a lost/injured body part.
How are cells replaced in regeneration?
Mitosis.
What is required for regeneration?
Portion of the Central disk.
What animals can regenerate?
Starfish, hydra, tadpoles, salamanders
What is parthenogenesis?
Development of underutilized egg into an adult organism.
What animals undergo parthenogenesis?
Bees and ants. Males are made this way. Females are from fertilized eggs.
How can parthenogenesis be stimulated?
Electric shock or pinprick of animal eggs.
All plants exhibit….
Alternation of generations.
Process of spore formation:
Diploid sporophytes produce haploid spores that makes haploid gametophytes.
What are meristems?
Undifferentiated tissues in plants.
What is vegetative propagation advantage?
No genetic variation and rapid.
Natural vegetative propagation:
Bulbs split.
Tubers are Underground stems with buds
Runner are stems above ground that can make new roots and upright stems
Rhizomes are woody underground stems
Examples of rhizomes
Ferns and iris
Examples of runners
Strawberry plants and lawn grass
Example of bulbs
Tulips
Example of tubers
Potatoes
Artificial Vegetative Propagation:
Used in agriculture:
Cut piece of stem can develop new roots in moist ground.
Auxins accelerate root formation.
Layering like in blackberries
What are auxins?
Plant hormones that accelerate root formation
What is layering in plants propagation?
Root is bent to ground and covered with soil to help plants take root.
