Igniting the Spark of Knowledge

Life Processes in Living Organisms

Part 1: Reproduction in Organisms

Complete study guide with questions and answers

1
Complete the table comparing reproductive types.

Answer:

Please complete this question from your textbook.
Hint for Comparison:

Compare characteristics such as: Number of parents involved, Genetic variation in offspring, Speed of reproduction, Examples in nature, Energy requirement, and Adaptability to changing environments.

2
Provide the missing term.

Answers:

a. The structure in humans responsible for the creation of male reproductive cells is the __________.
Testes
b. In human beings, the presence of the __________ chromosome determines the male sex.
Y chromosome
c. The __________ gland serves a common function in both the male and female hormonal control systems.
Pituitary gland
d. The embedding of the developing embryo occurs within the __________.
Uterus
e. The __________ method of reproduction occurs without the joining of male and female reproductive cells.
Asexual
f. An organism dividing into several fragments, each capable of developing into a complete organism, is a process named __________.
Fragmentation
g. Male reproductive spores (pollen grains) are generated through __________ cell division inside the anther cavities.
Meiosis
3
Finish the passage by using the appropriate words from the list. (Luteinizing hormone, endometrium of uterus, follicle stimulating hormone, estrogen, progesterone, corpus luteum)

Answer:

1
Follicle Stimulating Hormone (FSH) initiates the maturation of ovarian follicles.
2
These maturing follicles then release Estrogen.
3
Due to the effect of estrogen, the inner lining of the womb, the Endometrium of uterus, thickens or restores itself.
4
Once the follicle reaches full development, it bursts, triggered by the Luteinizing Hormone, releasing the ovum (ovulation).
5
The remnant of the ruptured follicle converts into the Corpus Luteum, which starts secreting progesterone and estrogen.
6
These hormones cause the uterine glands to become fully functional, preparing the womb for possible pregnancy.
4
Briefly answer the subsequent inquiries.

Answers:

(A) Describe and provide examples for the various strategies of non-sexual replication found in single-celled life forms.

Non-sexual replication in protozoans and other simple organisms involves:

Binary Fission

Process: Division of the parent cell to yield two identical daughter cells through mitosis or amitosis.

Examples: Bacteria, Amoeba, Paramecium, Euglena, and mitochondria.

Multiple Fission

Process: Organism forms a protective cyst, nucleus divides repeatedly, then cytoplasm divides to form many daughter cells.

Example: Amoeba under harsh conditions.

Budding

Process: Development of a small projection (bud) on parent cell, nucleus divides, bud separates when mature.

Example: Baker's Yeast (Saccharomyces cerevisiae).

(B) Explain the process known as In Vitro Fertilization (IVF).

IVF (In Vitro Fertilization) is a fertility treatment where:

  • The egg is fertilized outside the body in a laboratory container (in vitro = "in glass")
  • The resulting embryo is strategically placed into the woman's womb at an appropriate stage
  • Offers solution for couples struggling with conception due to issues like low sperm quality or blocked oviducts
(C) What protective measures should be implemented to maintain genital well-being?
Protective Measures:
  • Regular cleanliness of private/genital organs
  • Special hygiene during menstruation for women
  • Changing sanitary products regularly during menstrual cycles
  • Wearing clean, breathable underwear
  • Avoiding harsh soaps or chemicals in genital area
  • Seeking medical advice for any abnormalities or infections
(D) Define the menstrual cycle and summarize its phases.
Menstrual Cycle Definition:

The female reproductive system undergoes a regular sequence of hormonal and physical changes, lasting about 28–30 days, which begins at puberty. This repeating sequence is referred to as the menstrual cycle.

1
Follicular Phase: FSH stimulates development of ovarian follicle, which produces estrogen, leading to endometrial growth.
2
Ovulation: LH surge causes mature follicle to rupture, releasing egg (day 14 typically).
3
Luteal Phase: Corpus luteum forms and secretes progesterone, preparing uterus for potential pregnancy.
4
Menstruation: If no pregnancy occurs, progesterone levels drop, leading to shedding of endometrial lining (days 1-5).
5
Offspring born through sexual reproduction exhibit shared traits with their parents. Elaborate on this observation.

Answer:

Explanation:

The specialized cells (germ cells) that create gametes are diploid. They contain:

  • 22 pairs of body chromosomes (autosomes)
  • One pair of sex chromosomes (XX in females, XY in males)

These chromosomes transmit genetic information from both parents to the offspring through:

  • Meiosis: Reduces chromosome number by half in gametes
  • Fertilization: Combines genetic material from both parents
  • Inheritance: Offspring inherits a mixture of traits from both parents

This genetic recombination leads to noticeable similarities in characteristics while also creating unique combinations.

6
Draw and provide labels for the illustrations.

Diagrams to Draw:

Draw these diagrams in your notebook with proper labels
(A) Human Male Reproductive System

Labels to include:

  • Urinary Bladder
  • Ureter
  • Ductus Deferens (Vas Deferens)
  • Prostate Gland
  • Cavernous Tissue
  • Scrotum
  • Epididymis
  • Testis
  • Phallus (Penis)
(C) Flowering Plant with Reproductive Structures

Labels to include:

  • Stamen: Anther, Filament
  • Pistil: Stigma, Style, Ovary, Ovule
  • Corolla (Petal)
  • Calyx (Sepal)
  • Stalk (Pedicel)
(D) The Menstrual Cycle

Elements to include:

  • Ovarian Cycle: Ovum, Maturing Follicle, Egg Release, Corpus Luteum
  • Hormone Charts: Estrogen, Progesterone, LH, FSH levels
  • Uterine Cycle: Menses, Follicular Phase, Luteal Phase
  • Anatomy: Womb (Uterus), Ovary, Endometrium, Vagina, Fallopian Tube
7
List the following terms.

Answers:

(a) Male Reproductive Hormones
  • Follicle-Stimulating Hormone (FSH)
  • Luteinizing Hormone (LH)
  • Testosterone
  • Inhibin
(b) Ovarian Hormones
  • Estrogen
  • Progesterone
(c) Types of Twins
  • Monozygotic: Identical twins (from one fertilized egg)
  • Dizygotic: Fraternal twins (from two separate eggs)
(d) Sexually Transmitted Diseases
  • Syphilis
  • Gonorrhea
  • (Others: HIV/AIDS, Chlamydia, Herpes)
(e) Family Planning Methods
  • Intrauterine Devices (IUDs)
  • Hormone-based contraceptives (pills)
  • Barrier methods (condoms)
  • Emergency contraception
  • Permanent methods (vasectomy, tubal ligation)
8
State whether the following claim is accurate or inaccurate and provide a justification: "The sex of a baby is determined by the male parent."

Answer:

The sex of a baby is determined by the male parent.
Accurate (True)
Justification:

Chromosomal determination of sex:

  • Males: Possess XY sex chromosomes
  • Females: Possess XX sex chromosomes
  • Female gamete (egg): Always contributes X chromosome
  • Male gamete (sperm): Can contribute either X or Y chromosome

Fertilization outcomes:

  • X-sperm + X-egg → Female child (XX)
  • Y-sperm + X-egg → Male child (XY)

Thus, the sperm cell carries the deciding factor for the baby's sex, making the statement accurate.

9
Describe non-sexual reproduction in plants.

Answer:

Non-sexual reproduction in plants (Vegetative Propagation):

Generation of new plants from non-reproductive vegetative structures such as roots, stems, leaves, or buds.

Potatoes

Reproduce using the 'eyes' (buds) found on their tubers (modified stems).

Bryophyllum

Reproduces through small buds located along the edges of its leaves.

Sugarcane & Grasses

Grow from buds situated at the stem's joints (nodes).

Carrot & Radish

Propagate new plants via their specialized root structures (taproots).

Other Examples:
  • Ginger: Rhizomes (underground stems)
  • Onion: Bulbs
  • Strawberry: Runners (stolons)
  • Money Plant: Stem cuttings
10
Justify the assertion that modern procedures like gestational carriers (surrogacy), reproductive tissue banks (sperm banks), and in vitro fertilization (IVF) are beneficial to humanity.

Answer:

IVF (In Vitro Fertilization)

Benefit: Solution for couples with infertility issues

  • Blocked fallopian tubes
  • Low sperm count or motility
  • Unexplained infertility
  • Egg is fertilized in lab, embryo implanted in uterus
Surrogacy

Benefit: Helps women unable to carry pregnancy

  • Uterine abnormalities
  • Recurrent pregnancy loss
  • Medical conditions preventing pregnancy
  • Surrogate carries embryo from intended parents
Sperm Banks

Benefit: Assists with male infertility

  • Non-functional or absent sperm
  • Genetic disorders in male partner
  • Single women or lesbian couples wanting children
  • Screened donor sperm ensures health safety
Overall Benefits to Humanity:
  • Provides hope and solutions for infertile couples
  • Enables genetic screening to prevent hereditary diseases
  • Allows family planning for diverse family structures
  • Advances medical science and reproductive health
  • Reduces stigma around infertility
11
Detail the process of sexual reproduction in flowering plants.

Answer:

1
Pollination: Transfer of pollen grains from anther to stigma via air, water, insects, or animals.
2
Pollen Germination: Pollen grain absorbs moisture and germinates on stigma, forming pollen tube.
3
Pollen Tube Growth: Tube grows through style toward ovary, carrying two male gametes.
4
Double Fertilization: Unique to flowering plants
  • First fusion: One male gamete + egg cell → Zygote (develops into embryo)
  • Second fusion: Other male gamete + two polar nuclei → Endosperm (food storage)
5
Seed Formation: Fertilized ovule develops into seed containing embryo and endosperm.
6
Fruit Development: Ovary matures into fruit, protecting seeds and aiding in dispersal.
Key Terms:
  • Pollination: Transfer of pollen to stigma
  • Fertilization: Fusion of gametes
  • Double Fertilization: Two fusion events in flowering plants
  • Zygote: Fertilized egg, develops into embryo
  • Endosperm: Triploid tissue providing nutrition to embryo