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Questions and Answers

How does reproduction ensure the continuity of a species?

By passing on genes and ensuring genetic diversity through offspring.

What are the two main types of reproduction?

Asexual and sexual reproduction.

What is a characteristic of asexual reproduction?

  • Requires fertilization
  • Involves only one parent (correct)
  • Produces genetically diverse offspring
  • Involves two parents

    • Which of the following is NOT an advantage of asexual reproduction?

    <p>Requires a mate</p> Signup and view all the answers

    Match the following types of reproduction with their definitions:

    <p>Asexual reproduction = Involves one parent without fertilization Sexual reproduction = Involves two parents with fertilization Fertilization = The union of male and female gametes Meiosis = Cell division that creates gametes</p> Signup and view all the answers

    Do offspring produced by asexual reproduction have genetic variation?

    <p>False</p> Signup and view all the answers

    What is the process by which gametes are produced in sexual reproduction?

    <p>Meiosis.</p> Signup and view all the answers

    What is internal fertilization?

    <p>The process where fertilization occurs inside the female's reproductive tract.</p> Signup and view all the answers

    Which of the following is an advantage of sexual reproduction?

    <p>Increased genetic variation</p> Signup and view all the answers

    Which of the following is a disadvantage of asexual reproduction?

    <p>Lack of genetic diversity</p> Signup and view all the answers

    The process of meiosis results in cells that are __________.

    <p>haploid</p> Signup and view all the answers

    What type of fertilization is commonly seen in aquatic environments?

    <p>External fertilization.</p> Signup and view all the answers

    What role does oxytocin play during labor?

    <p>Oxytocin causes uterine contractions.</p> Signup and view all the answers

    Which hormones work in partnership during pregnancy?

    <p>Progesterone</p> Signup and view all the answers

    A gene is a segment of DNA that specifies a particular _______.

    <p>characteristic</p> Signup and view all the answers

    Mitosis produces four daughter cells.

    <p>False</p> Signup and view all the answers

    What is the difference between diploid and haploid cells?

    <p>Diploid cells have two alleles for each gene, while haploid cells have only one allele.</p> Signup and view all the answers

    What is the role of crossing over in meiosis?

    <p>To increase genetic variation</p> Signup and view all the answers

    Match the following terms with their definitions.

    <p>Gene = A segment of DNA on a chromosome Allele = Alternative forms of the same gene Chromosome = Made of DNA and structural proteins DNA = The genetic material in organisms</p> Signup and view all the answers

    What happens during DNA replication?

    <p>DNA separates and each strand serves as a template for a new complementary strand.</p> Signup and view all the answers

    Independent assortment occurs during anaphase of meiosis.

    <p>False</p> Signup and view all the answers

    What is the significance of DNA replication?

    <p>It ensures the genetic material is copied exactly for cell division.</p> Signup and view all the answers

    What structures are used for sexual reproduction in seed-producing plants?

    <p>Seed cones (gymnosperms)</p> Signup and view all the answers

    What is formed after fertilization in flowering plants?

    <p>Seed</p> Signup and view all the answers

    What changes occur in the ovary after fertilization?

    <p>It develops into a fruit.</p> Signup and view all the answers

    What are the advantages of spores in fungi?

    <p>No need for another organism to reproduce</p> Signup and view all the answers

    Seeds are unicellular.

    <p>False</p> Signup and view all the answers

    What is binary fission?

    <p>A form of reproduction in which a single cell divides into two equal parts.</p> Signup and view all the answers

    Which group of mammals gives birth to developed live young?

    <p>Placental mammals</p> Signup and view all the answers

    The fertilization occurs in the _____ tube.

    <p>fallopian</p> Signup and view all the answers

    What is the role of testosterone in the male reproductive system?

    <p>Stimulates the production of sperm</p> Signup and view all the answers

    What is the main function of the placenta in placental mammals?

    <p>Provides nourishment and protection to the developing embryo.</p> Signup and view all the answers

    The cervix stretches to allow the passage of a baby during childbirth.

    <p>True</p> Signup and view all the answers

    What triggers ovulation in females?

    <p>Surge of luteinising hormone (LH).</p> Signup and view all the answers

    The male reproductive organ that delivers urine or semen out of the body is called the _____

    <p>penis</p> Signup and view all the answers

    What pushes semen from the urethra into the vagina during muscular contractions?

    <p>ejaculation</p> Signup and view all the answers

    How long can sperm survive within the female reproductive tract?

    <p>3-5 days</p> Signup and view all the answers

    What is the ball of undifferentiated cells formed after fertilisation called?

    <p>morula</p> Signup and view all the answers

    What does the morula develop into as it continues to move down the oviduct?

    <p>blastocyst</p> Signup and view all the answers

    When does implantation typically occur after fertilisation?

    <p>around day 8 or 9</p> Signup and view all the answers

    What forms from the outer layer of cells in the blastocyst?

    <p>placenta</p> Signup and view all the answers

    What is the primary function of the placenta during pregnancy?

    <p>nutrient exchange</p> Signup and view all the answers

    From which structure does the umbilical cord develop?

    <p>egg yolk sac</p> Signup and view all the answers

    The blood of the mother and fetus mix during pregnancy.

    <p>False</p> Signup and view all the answers

    How are gases and nutrients exchanged between the mother and fetus?

    <p>diffusion</p> Signup and view all the answers

    What marks the beginning of the foetus stage?

    <p>12 weeks after fertilisation</p> Signup and view all the answers

    The three primary layers of the gastrula are ectoderm, mesoderm, and ______.

    <p>endoderm</p> Signup and view all the answers

    What hormone is produced by the developing embryo during the first trimester?

    <p>Human chorionic gonadotropin (hCG)</p> Signup and view all the answers

    What effect does oestrogen have during pregnancy?

    <p>prevents ovulation and menstruation</p> Signup and view all the answers

    Which hormone is primarily responsible for initiating labor?

    <p>oxytocin</p> Signup and view all the answers

    What is the function of relaxin during pregnancy?

    <p>relaxes maternal muscle joints and ligaments</p> Signup and view all the answers

    During which phase does DNA replication occur?

    <p>S Phase</p> Signup and view all the answers

    What is the role of mRNA in protein synthesis?

    <p>To carry the genetic information from DNA</p> Signup and view all the answers

    Which codon is known as the start codon?

    <p>AUG</p> Signup and view all the answers

    Centromeres are responsible for the movement of chromosomes during cell division.

    <p>True</p> Signup and view all the answers

    What does tRNA attach to in order to assist in translation?

    <p>an amino acid</p> Signup and view all the answers

    What are the two types of mutations mentioned?

    <p>Spontaneous mutations and mutagenic mutations.</p> Signup and view all the answers

    What is the primary role of DNA mismatch repair?

    <p>To replace incorrect base pairs</p> Signup and view all the answers

    Stop codons code for amino acids.

    <p>False</p> Signup and view all the answers

    The ______ is a polymer of many amino acids linked by peptide bonds.

    <p>polypeptide</p> Signup and view all the answers

    What is the importance of accurate DNA replication?

    <p>It ensures heredity and proper gene expression.</p> Signup and view all the answers

    What can affect the phenotypic expression of an organism?

    <p>the environment</p> Signup and view all the answers

    What do mutagens refer to?

    <p>Environmental factors that change DNA</p> Signup and view all the answers

    Which of the following statements about mutations is true?

    <p>Mutations can cause severe diseases.</p> Signup and view all the answers

    The strands of DNA in eukaryotes are __________, while in prokaryotes they are __________.

    <p>linear, circular</p> Signup and view all the answers

    Match the following processes with their descriptions:

    <p>Transcription = Assists in reading the genetic code to synthesize RNA Translation = Synthesizes proteins from amino acids Replication = Duplicates the DNA for cell division Gene expression = Determines the phenotype based on genotype and environment</p> Signup and view all the answers

    Where is the genetic code found in prokaryotic cells?

    <p>In the cytoplasm, in a region called the nucleoid.</p> Signup and view all the answers

    What is the role of tRNA in protein synthesis?

    <p>To bring amino acids to the ribosome</p> Signup and view all the answers

    What is the function of ribosomes?

    <p>They act as the site for polypeptide synthesis.</p> Signup and view all the answers

    Match the following types of RNA with their roles.

    <p>mRNA = Carries information from DNA to ribosomes tRNA = Brings amino acids to ribosomes rRNA = Structural part of ribosomes</p> Signup and view all the answers

    Study Notes

    Reproduction Overview

    • Reproduction is the process by which organisms produce offspring, ensuring continuity of species.

    Asexual Reproduction

    • Involves a single parent, producing genetically identical offspring.
    • Key process is mitosis; no gametes are involved.
    • Types include:
      • Parthenogenesis: Development from an unfertilized egg, as seen in certain reptiles and plants (e.g., brambles, dandelions).
        • Advantages: No need for males or pollinators.
        • Disadvantage: Lack of genetic diversity.
      • Regeneration: Parent organism splits and regenerates into new individuals.
        • Example: Planarians.
      • Fragmentation: Body breaks into pieces, with each piece developing into a new organism.
        • Example: Sponges, flatworms.
        • Advantage: Retained stem cells for regeneration, allowing for regrowth and reproduction.

    Sexual Reproduction

    • Involves two parents, producing genetically diverse offspring through the combination of their genes.
    • Key differences from asexual reproduction:
      • Genetic variation due to gamete combination.
      • Slower process requiring energy for finding mates and nurturing offspring.

    Comparison of Reproductive Methods

    • Asexual Advantages:

      • Rapid population increase.
      • No mate searching required.
      • Ideal in stable environments.

    • Asexual Disadvantages:

      • Low genetic variation, risking population decline in changing environments.

    • Sexual Advantages:

      • High genetic variation enhancing adaptability.
      • Natural selection favors stronger offspring.

    • Sexual Disadvantages:

      • Higher energy expenditure for finding mates and parental care.

    Fertilization Types

    • External Fertilization:
      • Large numbers of gametes released in open water.
      • Typically lower fertilization success.
      • Vulnerable zygote environment.
    • Internal Fertilization:
      • Male gametes fertilize eggs inside the female.
      • Higher success due to close proximity and protected development.
      • More parental care typically involved.

    Fertilization Process in Animals

    • Gametes produced by gonads through meiosis.
    • Somatic cells are diploid (2n), while gametes are haploid (n).
    • Zygote formation returns to diploid status.
    • Life stages alternate between haploid and diploid generations.

    Plant Reproduction

    • Asexual Reproduction in Plants:

      • Vegetative Propagation: New plants arise from roots, stems, leaves; examples include strawberries and potatoes.
      • Advantages and disadvantages in resource competition and genetic variation highlighted.

    • Sexual Reproduction in Plants:

      • Involves seed cones (gymnosperms) or flowers (angiosperms).
      • Pollination and Fertilization Steps:
        • Pollen grain lands on stigma and creates a tube toward the ovary.
        • Male gametes fertilize an ovule to form a diploid zygote and triploid endosperm.
        • Seeds develop within a protective fruit.

    Summary

    • Reproduction, both sexual and asexual, is vital for species continuity, adapting to environmental changes through genetic variation, and maintaining population stability through efficient reproductive strategies.### Seed Germination and Dispersal
    • Seeds germinate when conditions are suitable, developing into new plants.
    • Ovules develop into seeds protected by a seed coat; the zygote becomes a multicellular embryo.
    • The embryo forms cotyledons, root tips, and vascular tissues.
    • The ovary matures into fruit, which protects seeds and aids in their dispersal.

    Seed Dispersal Importance

    • Dispersal minimizes competition for resources like light, water, and nutrients.
    • Fruits can be dry (e.g., banksia pods) or fleshy (e.g., apples).
    • Dry fruits may have explosive mechanisms for dispersal; light seeds can float on air or water.
    • Fleshy fruits rely on animals for dispersal—animals consume the fruit, excreting seeds elsewhere.

    Seeds vs Spores

    • Seeds are multicellular with mechanisms for survival; found in flowering plants.
    • Spores are unicellular with limited survival facilities; found in non-flowering plants.

    Pollination Types

    • Wind-pollinated flowers: small, inconspicuous petals; abundant lightweight pollen for wind dispersal.
    • Bird-pollinated flowers: large, colorful petals; produce nectar; attract through visual and olfactory cues.
    • Insect-pollinated flowers: large, often fragrant petals; produce nectar to attract insects.

    Germination and Dormancy

    • Dormant seeds remain inactive until hydrated and environmental conditions are favorable.
    • Essential factors include water, oxygen, temperature, and daylight.

    Fungi Reproduction: Budding and Spores

    • Budding involves a small bud forming from the parent, leading to new individuals.
    • Advantages of budding include rapid reproduction and no need for another organism.
    • Disadvantages include genetic mutation and reduced diversity.
    • Spores are unicellular, lightweight, and enable rapid expansion, though survival rates are low.

    Bacterial Reproduction: Binary Fission

    • Common in prokaryotes; the cell divides into two equal daughter cells.
    • Advantages include rapid replication and independence in reproduction.
    • Disadvantages include genetic mutations leading to reduced diversity.

    Mammalian Reproduction Overview

    • Placental mammals have a uterus providing nourishment via the placenta and umbilical cord.
    • Marsupials give birth to underdeveloped young, which develop in external pouches.
    • Monotremes lay eggs and feed young with milk after hatching.

    Male Reproductive System

    • Testes in the scrotum produce and store sperm; key structures include seminiferous tubules and epididymis.
    • Accessory glands produce seminal fluid rich in nutrients to aid sperm motility.
    • Hormones such as testosterone and gonadotropins regulate sperm production and reproductive functions.

    Female Reproductive System

    • The uterus is where fertilized eggs implant and develop.
    • Ovaries store oocytes; fallopian tubes are the site of fertilization.
    • The menstrual cycle involves hormonal regulation affecting egg maturation, uterine lining preparation, and menstruation.

    Fertilization and Implantation

    • Fertilization occurs when haploid gametes form a diploid zygote in the fallopian tube.
    • Implantation of the blastocyst occurs around 8-9 days post-fertilization in the uterine wall.

    Placenta and Umbilical Cord Functionality

    • The placenta serves as an exchange organ, allowing nutrient and waste transfer without mixing maternal and fetal blood.
    • The umbilical cord develops to connect the embryo to the placenta for nutrient delivery.

    Pregnancy Stages

    • Pregnancy is calculated from the last menstrual period; embryo stage lasts from implantation to 9 weeks.
    • Major organ development occurs during the embryonic stage, completing by 8 weeks post-fertilization.

    Germ Layers in Embryonic Development

    • Gastrulation results in ectoderm (nervous system, skin), mesoderm (muscle, kidney), and endoderm (digestive and respiratory systems).

    Hormonal Control in Female Reproductive Cycle

    • Oestrogens regulate female reproductive functions and secondary characteristics.
    • The cycle involves ovulation, fertilization, and preparation of the uterus for potential pregnancy.### Development of the Foetus
    • The term "foetus" is used from 9 weeks after fertilisation until 38 weeks.
    • During this period, the foetus grows and develops organs.
    • Cells and tissues specialise to perform their specific functions.
    • The foetus is safeguarded within the amniotic cavity, a fluid-filled environment.

    Hormones in Pregnancy

    • Human Chorionic Gonadotropin (hCG)

      • Produced by the developing embryo and later by the placenta.
      • Maintains the corpus luteum, which secretes progesterone and oestrogen.
      • hCG levels decline after 12 weeks as the corpus luteum deteriorates.
      • Detected in urine for pregnancy tests.

    • Oestrogen

      • Initially produced by the corpus luteum; later the placenta and adrenal glands.
      • Suppresses GnRH, FSH, and LH to prevent ovulation and menstruation.
      • Rising levels during pregnancy support its maintenance.
      • Induces receptors on the uterus for oxytocin in the third trimester, facilitating labour.

    • Progesterone

      • Main hormone of pregnancy, produced by the corpus luteum and later by the placenta.
      • Maintains the endometrium and inhibits ovulation.
      • Promotes physical changes in the mother, including uterine enlargement and breast growth.
      • Levels rise throughout pregnancy to inhibit contractions.

    • Relaxin

      • Released by the corpus luteum and placenta during pregnancy, and by ovaries during birth.
      • Relaxes maternal joints and tissues to accommodate the growing foetus.
      • Facilitates cervical dilation during parturition.

    • Prolactin

      • Produced by the pituitary gland, increasing in the second trimester.
      • Stimulates milk production in mammary glands.

    Hormones in Birth (Parturition)

    • Oestrogen

      • Increases sensitivity of the uterus to oxytocin, promoting contractions.
      • Reduces effects of progesterone that suppress contractions.

    • Oxytocin

      • Secreted by the pituitary gland, critical for initiating and maintaining labour.
      • Triggers uterine contractions and facilitates the release of prostaglandins.

    • Prostaglandin

      • Produced by the uterine wall, aids in initiating labour and stimulating contractions.

    • Relaxin

      • Facilitates the dilation of the cervix and relaxation of pelvic ligaments.

    • Cortisol

      • Released from the foetus and uterus, increases oestrogen levels and decreases progesterone.

    Importance of Hormonal Balance

    • A correct hormonal balance is vital for sustaining pregnancy.
    • Increased prostaglandins heighten responsiveness to oxytocin, leading to labour.
    • After childbirth, oxytocin aids in uterine contractions to deliver the placenta and reduces uterus size.

    Genetic Material and Cell Replication

    • Genes are hereditary units located on chromosomes; humans have two copies of each autosomal gene.
    • Alleles are variations of genes that determine specific traits, such as height or seed colour.
    • Diploid individuals possess two alleles; haploid cells have one.

    Mitosis

    • Mitosis comprises four phases:
      • Prophase: Chromosomes condense and the nucleolus disappears.
      • Metaphase: Chromosomes align at the cell's equator.
      • Anaphase: Sister chromatids separate and move to opposite poles.
      • Telophase: Nuclei reform, concluding nuclear division.
    • Cytokinesis follows, splitting the cytoplasm into two daughter cells.

    Meiosis

    • Meiosis creates haploid gametes and promotes genetic diversity.
    • Essential for sexual reproduction, ensuring offspring inherit characteristics from both parents.

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    Description

    Explore how reproduction ensures the continuity of species through various mechanisms. This quiz analyzes both sexual and asexual reproduction methods across different organisms, highlighting their significance in biodiversity and species survival.

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