B2- Inheritance, Variation, Evolution Flashcards
Define sexual reproduction
The formation of a new organism by combining the genetic material of two organisms.
What are sexually produced offspring like?
Genetically similar to both parents but not identical to either
Define fertilization
The joining of two sex cells (egg and sperm) or the male and female gametes
Which gametes are in animals and flowering plants?
Sperm and egg in animals
Pollen and eggs in flowering plants
4 advantages of sexual reproduction
- Variation in offspring
- Can adapt to new environments
- Disease is less likely to effect all individuals in population
- Can use selective breeding
3 disadvantages of sexual reproduction
- Time and energy are needed to find a mate
- Impossible for an isolated individual
- Takes longer than asexual
Define asexual reproduction
Only involves one parent so there is no joining of sex cells during fertilisation
What are asexually produced offspring like?
Genetically identical to each other and their parent often called clones
Examples of asexual organisms
Bacteria
Production of fungi spores
Plant runners
Plant tubers
4 advantages of asexual reproduction
- Rapid population increase in favourable conditions
- Only one parent is needed
- Time and energy efficient as a mate is not needed
- Faster than sexual
3 disadvantages of asexual reproduction
- No variation in population
- Species may only be suited to one habitat
- Disease may affect all individuals in a population
List 3 organisms that reproduce both sexually and asexually
Malarial parasites
Fungi
Some plants
Malarial asexual and sexual reproduction facts
- Malarial parasites reproduce sexually in the host mosquito
- Malarial parasites reproduce asexually in the human host
Fungi asexual and sexual reproduction facts
- Fungi reproduce sexually to generate variation
- Fungi release spores by asexual reproduction
Plants asexual and sexual reproduction facts
- Plants use sexual reproduction to produce seeds
- Plants such as strawberries reproduce asexually by sending out runners, or daffodils when their bulbs divide
How do plants sexually reproduce?
Describe the process of meiosis
Answer in book
Describe the process of mitosis
Answer in book
Define DNA
Deoxyribonucleic acid.
The material inside the nucleus of cells, carrying the genetic information or code of a living being.
Describe the structure of DNA
A polymer, a large and complex molecule. It is made up of two strands called nucleotides forming a twisted ladder structure called a double helix. The nucleotides consist of a deoxyribose sugar, phosphate and base.
Nucleus
Contains cell DNA or genetic material
Chromosome
23 Pairs
Made up of DNA
Contains thousands of genes
Gamete
Sex cell
Gene
Codes for proteins section of DNA
Allele
Differently forms of a gene eg brown hair allele
Phenotype
Describing a characteristic eg brown eyes
Genotype
What alleles are present eg BB or Bb
Homozygous
2 copies of the same allele
Heterozygous
2 different alleles
Dominant
Needs one copy of the allele for the characteristic to be seen
Recessive
Only see characteristic if there are 2 allele copies
Human genome
Do later
What is a gene mutation?
Do later
List the 3 main symptoms of Cystic Fibrosis
- Difficulty breathing
- Difficulty digesting
-Difficulty reproducing
List the 1 symptom of Polydactyly
Born with one or more extra fingers
Are CF and Poly recessive or dominant
CF= Recessive
Poly= Dominant
How do you screen for genetic diseases?
What problems surround screening for genetic diseases?
How can we genetically modify organisms?
Human genome
