Topic 3 - reproduction and inheritance Flashcards
What are the differences between sexual and asexual reproduction?
Sexual reproduction involves the fusion of gametes, while asexual reproduction does not
Sexual reproduction leads to genetic variation, whereas asexual reproduction results in offspring that are genetically identical to the parent.
What is fertilisation?
The fusion of a male and female gamete to produce a zygote
The zygote undergoes cell division and develops into an embryo.
Describe the structures of an insect-pollinated flower.
Brightly colored petals, sweet nectar, and sticky stigma
These features attract insects for pollination.
Describe the structures of a wind-pollinated flower.
Small, dull petals, large amounts of lightweight pollen, and feathery stigmas
These adaptations facilitate pollen dispersal by the wind.
How does the growth of the pollen tube lead to seed and fruit formation?
The pollen tube grows to the ovule, allowing fertilisation and subsequent development into seeds and fruits
This process is crucial for the reproduction of flowering plants.
What are the conditions needed for seed germination?
Moisture, warmth, and oxygen
These conditions are essential for the metabolic processes necessary for germination.
How do germinating seeds utilise food reserves?
They use food reserves until the seedling can carry out photosynthesis
This is vital for the initial growth of the seedling.
How can plants reproduce asexually?
By natural methods (e.g., runners) and artificial methods (e.g., cuttings)
Asexual reproduction allows for rapid population increase without the need for seeds.
What adaptations are present in the male reproductive system?
Structures such as testes, vas deferens, and penis adapted for sperm production and delivery
These adaptations ensure effective reproduction.
What adaptations are present in the female reproductive system?
Structures such as ovaries, fallopian tubes, and uterus adapted for egg production and nurturing embryos
These adaptations facilitate fertilisation and development.
What roles do oestrogen and progesterone play in the menstrual cycle?
Regulate ovulation and prepare the uterus for potential pregnancy
These hormones are crucial for reproductive health.
What is the role of the placenta in embryo nutrition?
Facilitates nutrient and gas exchange between the mother and developing embryo
The placenta is essential for the embryo’s growth and development.
How does amniotic fluid protect the developing embryo?
It cushions the embryo and maintains a stable temperature
This protection is vital for the embryo’s development.
What roles do oestrogen and testosterone play in secondary sexual characteristics?
Oestrogen promotes female traits, while testosterone promotes male traits
These hormones are key in sexual differentiation during puberty.
What is a genome?
The entire DNA of an organism
It contains all the genetic information necessary for the organism’s development and functioning.
What is a gene?
A section of a molecule of DNA that codes for a specific protein
Genes are the basic units of heredity.
Where are chromosomes located?
In the nucleus of a cell
Chromosomes contain genes that dictate traits.
Describe the structure of a DNA molecule.
Two strands coiled to form a double helix, linked by paired bases: A with T, C with G
This structure is essential for DNA replication and function.
How does an RNA molecule differ from DNA?
RNA is single-stranded and contains uracil (U) instead of thymine (T)
This difference is crucial for RNA’s role in protein synthesis.
What are the stages of protein synthesis?
Transcription and translation
Involves mRNA, ribosomes, tRNA, codons, and anticodons.
What are alleles?
Alternative forms of a gene that give rise to differences in inherited characteristics
Alleles contribute to genetic diversity within a population.
Define dominant and recessive.
Dominant: allele that masks the effect of another; Recessive: allele that is masked
These terms are fundamental in genetics.
What is the meaning of homozygous and heterozygous?
Homozygous: two identical alleles; Heterozygous: two different alleles
These classifications are important for predicting genetic outcomes.
What is phenotype?
The observable physical characteristics of an organism
Phenotype results from the interaction of genotype and environment.
What is genotype?
The genetic makeup of an organism
Genotype determines potential traits.
What is polygenic inheritance?
Inheritance of traits controlled by multiple genes
Most phenotypic features are influenced by this type of inheritance.
What is a monohybrid inheritance?
Inheritance pattern involving one trait
It can be illustrated using a genetic diagram.
How do you interpret family pedigrees?
By analyzing inheritance patterns and relationships among family members
This helps track genetic traits across generations.
How do you predict probabilities of outcomes from monohybrid crosses?
Using Punnett squares to calculate the likelihood of different genotypes
This method visualizes genetic combinations.
How is the sex of a person controlled?
By one pair of chromosomes: XX in females and XY in males
This chromosomal difference is fundamental to sex determination.
Describe the determination of the sex of offspring at fertilisation.
Involves the combination of X and Y chromosomes from parents
The genetic diagram can illustrate this process.
What happens during mitosis?
A diploid cell divides to produce two identical daughter cells
Mitosis is essential for growth and repair.
What is the role of meiosis?
Produces four haploid gametes, each with half the number of chromosomes
Meiosis is crucial for sexual reproduction and genetic diversity.
How does random fertilisation produce genetic variation?
By combining different gametes, leading to unique genetic combinations
This process enhances genetic diversity in a population.
What is the diploid number of chromosomes in human cells?
46
The haploid number is 23.
What types of variation exist within a species?
Genetic, environmental, or a combination of both
Variation is important for adaptation and evolution.
What is a mutation?
A rare, random change in genetic material that can be inherited
Mutations can lead to new traits and genetic diversity.
