CH. 2 - Reproduction

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1. Key words

1. Anther - terminal sac of stamen that makes the spore (male)

2. Apical Meristem - tip of root/stems

3. Auxins - synthetic plant hormones that makes root develop faster

4. Bulbs - Make new plant with several bulbs

5. Chromatin - DNA is called this when uncoiled

6. Corpus Luteum - makes estrogen and progesterone.  From ruptured follicle

7. Cotyledons - seed leaves.  Dicot have 2, monocot has 1.

8. Cytokinesis - cell division

9. Ejaculatory Duct - the path to the urethra

10. Endometrium - uterine wall (thickened by Estrogen)

11. Endosperm - grows and feeds the embryo. 

1. In dicots, cotyledon absobs the endosperm

12. Epicotyl - precursor to upper stem and leaves

13. Epididymis - the thing that tests is attached to

14. Filament (stamen) - a stalk that holds the anther

15. Follicle (ovary) - sac of cells. Protects, nourishes immature cells. Produce estrogen

16. Follicular phase - FSH from anterior pituitary stimulates growth of follicle

17. Karyokinesis - Nuclear division

18. Lateral Meristem - Cambium.  This allows growth in diameter

19. Luteal Phase - Luteinizing hormone causes follicle to turn into corpus luteum

20. Menstruation - if ovum is not fertilized, corpus luteum atrophies, endometrium expelled

21. Meristems - undifferentiated tissues in plants that can grow to be an adult plant

22. Ovary (plant) - enlarged base of the pistil  Contains ovary

23. Ovulation - luteinizing hormone surge and follicle bursts releasing ovum

24. Parthenogenesis - development of unfertilized egg

25. Petals - specialized leaves that protects the pistil.  Attracts birds and insects

26. Pistil - female organ of the flower

27. Rhizomes - woody underground stems that can develop upright stems

28. Runners - stems running above and along the ground like lawn

29. Seed Coat - develops from outer covering of the ovule.

30. Seminiferous tubules - Sperms made here

31. Sepal - the green leafy part outside of the main flower

32. Stamen - male organ of the flower

33. Stigma - sticky top part that catches pollen (spores)

34. Style - the tube like structure that guides the pollen along

35. Testosterone - regulates secondary male sex characteristics

36. Tubers - underground stems with buds that can develop into adult

37. Urethra - right before the penis, it's shared by both reproductive and excretory

38. Vas Deferens - What the epididymis is attached to

39. Hypocotyl - develops into stem and root

1. Cell Division

1. In unicellular organisms, cell division is reproduction while in multicellular organism, it's for growth and repair.

2. Two types, mitosis and meiosis.

3. Stages of Mitosis

1. Interphase

1. 90% of cell life in interphase.

2. Prophase

1. Chromosomes condences

2. Centrioles separate and move toward opposite poles of cells

3. Spindal apparatus forms between the centriole and nuclear membrane dissolves

3. Metaphase

1. Centriole pairs are at opposite pair of the poles

2. The chromosome are at the center of the cell called metaphase plate

4. Anaphase

1. The centromeres are split so each chromatid has its own distinct centromere

5. Telophase

1. The spindle apparatus disappears.

2. Nuclear membrane forms

3. Chromosomes uncoil

6. Cytokinesis

1. The cytoplasm divides into two daughter cells

2. Cleavage furrow forms and pinches through the cell.

7. Difference with Plant Cells

1. Plants lack centriole, so the spindle apparatus is synthesized by microtubule organizing centers

2. Plants form a cell plate that divides the cells

4. Stages of Meiosis

1. Interphase

1. Chromosomes are replicated into 2N number of sister chromatids

2. Prophase I

1. Chromatin condenses into chromosomes

2. Spindle apparatus forms

3. Nucleoli and nuclear membrane disappears

4. Homologous chromosomes come together and synapsis, crossing over occurs

5. Tetrads are formed

3. Metaphse I

1. The homologous pairs align at the equatorial plate

4. Anaphase I

1. Disjunction, or the homologous pairs separate and pulled to the opposite poles occurs

5. Telophase I

1. The nuclear membrane forms around each new nucleus

6. Prophase II

1. They line up again

7. Metaphse II

1. Aligned at the equatorial plate

8. Anaphase II

1. The sister chromatids separate

9. Telophase II

1. The nuclear membrane forms again.

Asexual Reproductive Mechanisms

1. General

1. Production of offspring without fertilization

2. Carbon copies of parent except when mutation occurs

3. Prevalent  amongst invertebrate, not vertebrates in animals

4. All plants go through asexual reproduction in some form

2. Non-Plants

1. Fission

1. Seen in prokaryotic organisms

2. DNA replicates, and new plasma membrane and cell wall grows and divides the cell.

3. Happens in amoebae, paramecia, algae, bacteria

2. Budding

1. Replication of nucleus followed by unequal cytokinesis

2. Cell membrane pinches inward to form a new cell that is smaller but identical to parent

3. The new cell may separate immediately or be just an outgrowth and separate later

4. Happens in hydra and yeast

3. Regeneration

1. Regrowth of lost or injured body part via Mitosis

2. Hydra and Starfish can regenerate entire body from just the arm as long as it contains a piece of central disk

4. Parthenogenesis

1. Development of an unfertilized egg into an adult organism

2. Happens in bees and ants where worker bees and queen are from fertilized while normal males are from unfertilized

3. Artificial parthenogenesis can happen to animals via electric shock

3. Plants

1. General

1. All plants have alternation of generations where it goes from diploid to haploid

2. Spore Formation

1. Diploid sporophyte generation produces haploid spores

2. Haplod spores develop into the haploid gametophyte generation which would need to be fertilized to go back to sporophyte generation

3. Vegetative propagation

1. Meristems, undifferentiated tissues in plants that can grow into an adult plant

4. Natural Vegetative Propagation

1. Bulbs - growth that split to form several bulbs and can then grow into adult

1. Happens with tulips and daffodils

2. Tubers - underground stems with buds that can grow into adult

3. Runners - stems running above and along the ground that can produce new roots

1. Strawberry and lawn grass

4. Rhizomes (stolons) - woody, underground stems that can develop new upright stems

1. Ferms and iris plants

5. Artificial Vegetative Propagation

1. A cut from stem can grow with help of hormone called auxins

2. Stems of certain plants will grow and take root if bent to the ground, this is called layering.

3. Stem of one plant called the scion can be attached to another called stock and new plant results.

Sexual Reproductive Mechanisms

1. General

1. Two parents are involved and result in genetically unique offspring

2. Requires two gametes fertilizing each other

2. Sexual Reproduction in Animals

1. Gonads

1. Gametes are produced in the specialized organs called gonads.

2. Male gonads are called testes, produces sperm in the seminiferous tubules

3. Female gonads are called ovaries, produce oocytes

4. Hermaphrodites have both functional male and female gonads

1. Earthworms and hydra have both

2. Spermatogenesis

1. Sperm production happens in seminiferous tubules

2. Spermatogonia (diploid) undergoes meiosis to produce 4 sperms

3. Sperm

1. Consists of head, tail, neck and body

1. Head consists of almost entirely of nucleus with paternal genome

2. Tail (flagellum) propels the sperm

3. Neck and body are full of mitochondria for energy

3. Oogenesis

1. Production of females gametes in ovaries

2. One diploid female sex cells undergoes meiosis to produce single mature egg

1. Each meiotic division produces a polar body

2. Polar body is a small cell that contains little more than nucleus

3. Polar bodies usually die quickly

3. Mature ovum contains most of the cytoplasm, RNA, organelles, and nutrients needed by developing embryo

4. Fertilization

1. General

1. Species that care for their young, produces far fewer eggs

2. External

1. Vertebrates that reproduce in water (fish and amphibian)

2. Females lay the eggs and the males deposits sperm in the vicinity

3. Internal

1. Practiced by terrestrial vertebrates and provides direct route for sperm

2. Females need not produce so many eggs

3. Human Reproduction

1. Male Reproductive Physiology

1. Testes located in pouch called scrotum which keeps the testes 2-4 degrees lower in temperature

2. Sperms get out of the penis in the following order

1. Seminiferous Tubules - made here

2. Epididymis - The thing that testes is attached to

3. Vas deferens - the thing that's attached to the epididymis

4. Ejaculatory Duct - the path to exit

5. Urethra - right before the exit

6. Penis - The final stretch

3. Urethra is common passageway for both reproductive and excretory system

4. Testes are also site of testosterone production

1. Testosterone regulates secondary male characteristics

1. Facial and pubic hair, and voice changes

2. Female Reproductive Anatomy

1. Ovaries are found in the abdominal cavity, below the digestive system

1. Consists of thousands of follicles

2. Follicles are multi-layered sac of cells that contains, nourishes, and protects an immature ovum

1. Follicles produces estrogen

2. Once a month, immature ovum is released into nearby oviduct and it leads via the fallopian tube to the uterus.

3. Uterus is the site of fetal development.

4. Closer to the vagina is the cervix

5. The vagina canal is the site of sperm deposition during intercourse

6. At birth, all the eggs a female will ovulate are already present in the ovaries

3. Female Sex Hormones

1. Ovaries produces and secrete estrogens and progesterone

1. Ovaries is regulated by LH, FSH

2. Production of LH and FSH is regulated by GnRH

2. Estrogen

1. Steroid hormones necessary for normal female maturation

2. Stimulate the develop of female reproductive tracts

3. Stimulates the thickening of endometrium (uterine wall)

4. Contributes to secondary sexual characteristics and sex drive

5. Secreted by ovarian follicles and corpus luteum

3. Progesterone

1. Secreted by corpus luteum during luteal phase of the menstrual cycle

2. Stimulates the development an maintenance of the endometrial walls to prepare for implantation

4. Menstrual Cycle

1. Secretions by ovaries, hypothalamus, and anterior pituitary all play a role in the reproductive cycles

2. From puberty to menopause, these hormones result in monthly pattern PMS

3. Can be divided into follicular phase, ovulation, luteal phase, and menstration

1. Follicular phase

1. Starts with cessation of menstrual flow from previous cycle

2. Follication stimulating hormones (FSH) from anterior pituitary promotes the development of follicles

3. Development of follicles causes secretion of estrogen

2. Ovulation

1. Caused by surge of luteinizing hormone (which is caused by peaking of estrogen level)

2. Midway through the cycle, ovulation occurs

3. A mature ovarian follicle bursts and releases an ovum

3. Luteal phase

1. Luteinizing hormone induces the ruptured follicle to turn into corpus luteum

2. Corpus luteum secretes estrogen and progesterone

3. Progesterone causes the glands of endometrium to mature and produces secretions that prepare endometrium for implantation

4. Menstruation

1. If ovum is not fertilized, corpus luteum atrophies

2. The lack of progesterone and estrogen causes the endometrium to become weak and slough off

3. This causes the menstral flow

4. If fertilization occurs, the developing placenta produces hCG (human chorionic gonadotropic) which would maintain the corpus luteum.

5. Until the placenta is developed, the corpus luteum will stay and keep estrogen and progesterone coming

4. Sexual Reproduction in Plants

1. General

1. Characterized by alternating between diploid sporophyte and haploid gametophyte generations

2. Sporophyte, via evolution, are becoming more dominate

3. The order > Sporophyte (2N) >> Spores (1N) >> Gametophyte (1N) >> fertilization >> Sporophyte (2N)

2. Gametophyte Generation

1. Haploid gametophyte produces gametes by mitosis

2. Thus, gametophyte reproduces sexually while sporophyte reproduces asexually

3. Gametophyte is dominate generation in mosses.

1. The sporophyte of mosses is dependent on the gametophyte to survive

3. Sporophyte Generation

1. The sporophyte produces spores via meiosis

1. In ferns, sporophytes are dominate

2. In angiosperms (flowering plants), sporophytes are dominate

5. Sexual Reproduction in Angiosperms

1. General

1. The flower is the reproductive structure

2. Some species have flower that contain only male or female.  Some have both

2. Parts of a flower

1. Stamen

1. Male organ of the flower and consists of stalk like filament with a sac called anther.

2. Anther is what produces the haploid spores that become a pollen grain

2. Pistil

1. Female organ of the flower, consists of stigma, style, and ovary

2. Stigma is the stick part that catches spores

3. Style - tube that guides the pollens along

4. Ovary - enlarged base of pistil

3. Petals and Sepals

1. Decorations

3. Fertilization

1. Pollen grains goes from anther to the stigma, and the sperm nucleic splits and makes the male gametes

2. Female gametophyte - developed in ovules from one out of 4 spores

3. This is the embryo sac and contains nucleic including two polar nucleic

4. Fertilization occurs when sperm nucleus fuses with the egg nucleus to develop into embryo.

5. Other sperm nucleus fuses with 2 polar bodies to form endosperm.

4. Seed Formation

1. Embryo consists of

1. Epicotyl - precursor to upper stem and leaves

2. Cotyledons - seed leaves.  Dicot have 2, monocot has 1.

3. Hypocotyl - develops into stem and root

4. Endosperm - grows and feeds the embryo. 

1. In dicots, cotyledon absorbs the endosperm

5. Seed Coat - develops from outer covering of the ovule.

5. Seed Dispersal

1. Fruits is the usual seed carrier

1. Formed from ovary walls, base of the flower, and other flower components

2. The seed is released from the ovary, and will germinate under the right conditions

6. Plant development

1. Growth in advanced plants depends on meristem cells.

2. Eventually, meristem cells would elongate and differentiate into different cell types

3. Apical meristem - found on the tip of the roots and stems, growth only here

4. Lateral meristem - cambium in another word, located between xylem and phloem.

1. Permits growth in diameter

2. Can differentiate into either xylem or phloem cell

3. Not active in monocots (grasses) or herbaceous dicots.