Science Unit 8 SEXUAL REPRODUCTION Flashcards
Definition of Reproduction?
- It is the production of new organisms.
- It is to ensure the continuation of life of a living organism
- Two types: Sexual and Asexual
Characteristics of Sexual Reproduction?
- It involves the fusion of the nuclei of two sex cells to form a fertilised egg (also known as zygote)
- It typically involves two parents
- The two sex cells are: Sperm and Egg (Both are gametes)
EXAMPLE: Fertilisation in Humans.
Characteristics of Asexual Reproduction?
- It does not involve the fusion of the nuclei of sex cells.
- It typically involves only one parent.
EXAMPLE: A bacterial cell divides into two identical “daughter cells”.
Definition of Heredity?
- It is the passing down of genetic material from one generation to the next during Sexual Reproduction.
What happens during Fertilisation?
A sperm and Ovum unite to form a new diploid organism
- Gamete are Haploid (Sex cells)
- Zygote is Diploid (Fertilised Egg)
Sex cells ->
Gamete (Haploid)
Fertilized egg ->
Zygote (Diploid)
Definition of Heredity?
It is the passing down of genetic material from one generation to the next during reproduction.
What is genetic material?
- It is found in the nucleus of the sex cell
- It contains a set of instructions that guide the development and treaits of the offspring
What are traits?
They are determined by genes.
Exaplain how Genetic material is passed down during reproduction:
When the nuclei of the sex cells fuse together, they form a zygote which contains the genetic material of both parents, though it is not entirely the same as the parents.
Definition of Variation?
- It refers to the differences in the combination of genetic material among individuals within a population.
Explain the process of inhereting traits:
- Inheriting traits is a random process. This means that offspring can inherit any possible combination of traits from its parents.
Reasons of inheriting traits:
- These sex cells combine randomly to restore the full set of genetic material in the off spring.
- They contain both the parents’ genetic material, but not completely the same comnbination as the parents. (Each parent carries two genetic material [Diploid])
(Their sex cells contain only one set of genetic material [Haploid])
Examples of inheritable diseases:
Sickle Cell Anaemia, Albinism, Cystic Fibrosis
Definition of Puberty?
It is the period of human growth and physical developments in which a girl or boy matures sexually.
Definition of Hormones:
A hormone is a chemical messenger in the body that regulates various functions like growth, metabolism, and mood.
Theory of “Which sperm won, Which egg present”
As the sex cells fuse together randomly, the traits inherited by the off spring are determined by chance.
Definition of Puberty?
It is the period of growth and physical development in which a girl or boy matures sexually.
Traits of PUBERTY in a GIRL:
- When: Typically 10-12 years old
- Sex Hormones: Oestrogen and Progesterone
- Common Changes:
1. Breats enlarge
2. Hips become rounder and broader
3. Growth of pubic hair and armpit hair
4. Increased height and weight
5. Ovulation begins
6. Menstruation begins
What happens during puberty? (2 things, Hormone + Maturation of sex organs)
- The production of sex hormones (Testostrone {MALE}, Oestrogen and Progesterone {FEMALE}
- Sex organs become fully functional and begin to produce mature sex cells.
Why is it important for the Hips to become rounder and broader? (sexual maturation of females)
- A broader pelvis provides a more accommodating birth canal, which is essential for childbirth.
- Increased fat deposition in the hips and thighs helps support future reproductive functions, including pregnancy and breastfeeding.