Cell Division and Asexual Reproduction

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Questions and Answers

What function does the micropyle serve in seeds?

It helps in the dispersal of the seeds.

It forms part of the wall of the ovary.

It facilitates the attachment of fruit to the plant.

It remains as a scar on the seed. (correct)

Which of the following describes an advantage of fruit and seed dispersal?

Enhances direct growth near the parent plant.

Increases competition for resources.

Encourages crowding, which fosters community.

Allows colonization of new growth areas. (correct)

How do parachute fruits like dandelions primarily disperse?

Through water currents.

Via explosive splitting mechanisms.

By being floated by slight air currents. (correct)

By being cushioned within animal fur.

What is the biological definition of a fruit?

A fertilized ovary. Signup and view all the answers

Which mechanism does not describe an animal dispersal method?

Seeds that explode from the pod. Signup and view all the answers

What is a significant characteristic of asexual reproduction?

Offspring are genetically identical to the parent. Signup and view all the answers

Which of the following is a type of asexual reproduction that involves the development of eggs without fertilization?

Parthenogenesis Signup and view all the answers

What is the process called when a part of a plant is used to grow a new individual?

Fragmentation Signup and view all the answers

Which of the following advantages is NOT associated with asexual reproduction?

Greater genetic diversity in offspring. Signup and view all the answers

In which type of organism does simple binary fission primarily occur?

Bacteria Signup and view all the answers

What is the main advantage of vegetative propagation compared to seed propagation?

It allows for rapid growth of clones. Signup and view all the answers

During which phase of the cell cycle does DNA replication occur?

Interphase Signup and view all the answers

What is a primary disadvantage of asexual reproduction?

Overcrowding and competition Signup and view all the answers

Which process is unique to sexual reproduction?

Zygote formation Signup and view all the answers

In which type of reproduction do offspring have genetic variations?

Sexual reproduction Signup and view all the answers

What characterizes asexual reproduction regarding offspring quantity?

Produces a large number of identical offspring Signup and view all the answers

Which reproductive process introduces genetic variability in a population?

Meiosis Signup and view all the answers

What type of reproductive organ does a hermaphrodite plant possess?

Both male and female organs Signup and view all the answers

What is a key advantage of sexual reproduction?

Maintains a good strain of species Signup and view all the answers

Which division process is associated with asexual reproduction?

Mitosis Signup and view all the answers

What is one common occurrence of asexual reproduction?

In simple plants and animals Signup and view all the answers

What is the first step when preparing to observe mitosis in plant cells?

Clean both the slide and the objective Signup and view all the answers

Which phase of the cell cycle is most likely visible when examining the apical meristem of an onion root?

Interphase Signup and view all the answers

How is the percentage of cells in each stage of mitosis calculated?

Divide the number of cells in a stage by total cells and multiply by 100 Signup and view all the answers

What magnification is used to first focus on the onion root tip?

4X Signup and view all the answers

Which stage accounts for the smallest percentage of cells in the observed mitotic process?

Telophase Signup and view all the answers

What is the total number of cells counted across all phases during the observation?

36 Signup and view all the answers

What should be done after locating the apical meristem and switching to high power?

Adjust the diaphragm for improved visibility Signup and view all the answers

How many minutes does an onion cell take to undergo mitosis based on the study?

1440 minutes Signup and view all the answers

What is the function of staining the onion root tip before observation?

To help visualize chromosomes Signup and view all the answers

What is the primary function of the sepals in a flower?

To protect the flower in the bud Signup and view all the answers

Which part of a flower is specifically responsible for producing male gametes?

Anther Signup and view all the answers

During the process of pollination, what role does the stigma play?

It receives pollen grains Signup and view all the answers

What transformation occurs to the flower's receptacle after fertilization in some species?

It becomes fleshy and edible Signup and view all the answers

What is the primary function of the nectary glands in a flower?

To produce a sugary solution that attracts insects Signup and view all the answers

What is typically found in the ovary of a flower?

Ovules Signup and view all the answers

How many stamens are typically found in a Lupin flower?

10 Signup and view all the answers

What is the significance of the guide lines on the petals of a flower?

To help attract pollinators Signup and view all the answers

In the context of flower structure, what is the main role of the carpel?

To produce female gametes Signup and view all the answers

Which of the following statements about unisexual flowers is accurate?

They have only male or only female organs Signup and view all the answers

Study Notes

Cell Division

Asexual reproduction produces offspring that are genetically identical to the parent.
This is common in plants.
Types of asexual reproduction include: simple binary fission, parthenogenesis, and vegetative propagation.

Types of Asexual Reproduction

Simple binary fission in bacteria: The bacterial DNA duplicates, and the cell divides into two.
Parthenogenesis in plants: Eggs develop into plants without fertilization. Meiosis is not involved, and the egg is diploid.
Vegetative propagation in plants: This process produces genetically identical offspring. Methods include fragmentation (using cuttings), and the production of specialized structures like tubers and runners.

Advantages of Vegetative Propagation

Faster than seed propagation.
Genetically identical offspring ensure a superior plant produces unlimited copies.
Can produce a large number of offspring.

Cell Cycle

The cell cycle is the regular sequence of events from one cell division to another.
It has three phases: interphase, nuclear division (mitosis), and cell division.

Mitosis

During mitosis, a parent cell divides to produce two genetically identical daughter cells.
Chromosomes copy themselves before mitosis.
Cancer cells divide by mitosis, creating copies of the parent cell.
Uncontrolled cell division increases cancer risk.

Importance of Mitosis

Growth of the organism
Tissue Repair
Asexual reproduction
Development: increase in cellular complexity to specialize functions
Initially, a zygote rapidly divides by mitosis many times to make a large mass of genetically identical cells.

Stages of Mitosis

The notes describe details of prophase, metaphase, anaphase, and telophase stages in graphic form

Importance of Meiosis

Meiosis is a reduction division.
Involved in producing gametes (haploid cells) for sexual reproduction.
Gametes are variable due to crossing over and independent assortment.

Stem Cells

Undifferentiated cells that divide by mitosis.
Types include embryonic stem cells and adult stem cells
Embryonic stem cells can differentiate into any specialized cell type.
Adult stem cells differentiate into specific cell types.

Sexual Reproduction in Flowering Plants

Flowers are the reproductive organs of plants.
Flowers can be bisexual (have both male and female organs) or unisexual (have only male or female organs).
Structures in a typical flower include sepals, petals, stamens (with anthers and filaments), and a carpel (with stigma, style, and ovary).
Functionally, sepals protect the bud. Petals attract pollinators. Stamens produce pollen (male gametes). Carpels produce ovules (female gametes).

Pollination

Transfer of pollen from anther to stigma
Types include self-pollination (within the same flower or plant) and cross-pollination (between different flowers or plants).
Factors affecting pollination include flower structure (e.g., wind or insect pollination), time differences in gamete maturation.

Methods of Pollination

Insects: insects attracted to flowers by color and scent, pollen sticks to their bodies and transferred to another flower.
Wind: pollen grains are carried by the wind, have smooth, light pollen and feathery structures.

Development of Pollen Grains and Male Gametes

Pollen grains develop from pollen mother cells through meiosis.
Pollen walls are very resistant.
The mature pollen grain contains two nuclei (generative and pollen tube nuclei).

Development of Ovules and Female Gametes

Ovules develop within the ovary of the flower.
A specialized part of the ovule called the embryo sac contains the egg cell.
Fertilization occurs after pollen has reached a stigma.

Fertilization in Plants

Union of pollen grain and egg cell in the ovule
A pollen tube grows from the pollen, carrying male gametes to the egg
Double fertilization: one sperm fuses with egg (embryo) and one sperm fuses with polar nuclei to form endosperm.

Seed Germination

Development of the zygote to embryo.
Breakdown of stored food reserves (starch and proteins) through enzymes to provide resources for embryo growth.
Stages including absorption of water, radicle formation, plumule (shoot) formation, and the use of stored food reserves from cotyledons.

Dispersal of Seeds and Fruits

Method of carrying seeds and fruits away from the parent plant to a new location (important for preventing overcrowding and disease).
Methods include wind, water, animals.

Practical Work: Germination of Mustard Seeds

Set up different conditions for seed germination (water, warmth, oxygen, and light).
Monitor the germination process through observation.

Reproduction in Humans- Male Reproductive System

Structures and functions of the testes , epididymis , vas deferens , urethra , prostate gland , and seminal vesicles
External Genitalia include penis
Function of each part in the reproductive process

Reproduction in Humans-Female Reproductive System

Ovaries: are the female sex glands that produce ova (eggs) and sex hormones during ovulation phase
Oviducts (fallopian tubes): the site of fertilization.
Uterus (womb): the site for implantation of a fertilized egg, development of the embryo, and pregnancy.
Cervix: the opening to the uterus
Vagina: receives the penis during sexual intercourse, and facilitates the passage of the baby during birth
External Genitalia include vulva (or external genitals)

Puberty

The period of sexual maturation
Physical changes (hair growth, voice change, breast development, and reproductive system maturation).
Emotional and behavioral changes due to hormonal changes
Timing and differences between sexes

Gametes

Gametes (sperm and ova) are the reproductive cells.
Size, Number and structure differ between sperm and ovum.

Female Sexual Cycles

Hormonal control (FSH, LH, estrogen, and progesterone) that regulate the ovarian cycle and uterine lining.
Phases of the cycles: menstruation, follicular phase, and luteal phase.
Changes in the lining of the uterus (endometrium) during the cycle

Ovarian and Menstrual Cycle

The ovarian cycle regulates the production of ova and related hormones.
The menstrual cycle regulates the changes in the uterine lining in response to the ovarian cycle.

Fertilization and Implantation

How sperm reaches the egg
Sequences of events starting from fertilization leading to implantation (zigotic division into embryo)

Embryonic Membranes

The chorion, amnion, and amniotic fluid play in protecting and nourishing the developing embryo (fetus)

Care of Mothers during Pregnancy

Balanced diet, avoiding smoking, and no drugs except under consultation with a doctor
Immunizations for the mother or fetus health (German measles).

Feeding a Baby

Advantages of breast milk versus formula milk
Factors related to the choice of how to feed babies and the problems related to these choices.

Infertility - causes, treatments

Causes of infertility in males and females.
Techniques used to treat infertility (fertility drugs, and in vitro fertilization)

Family, social and economic issues arising from decisions regarding reproduction

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Description

This quiz covers the fundamentals of cell division and the various methods of asexual reproduction in plants, including binary fission, parthenogenesis, and vegetative propagation. Understand the advantages of these reproduction methods and how they contribute to plant growth and sustainability.