B12 - Reproduction Flashcards
Asexual Reproduction
- Involves 1 parent Gametes
- No mix of genetic information, so offspring is genetically identical to its parent, these are clones
- Involves Mitosis, not Meiosis
Asexual Reproduction Uses
- Plants, Fungi, Bacteria produce asexually
- Our cells asexually reproduce to repair to replace damaged tissue, done by Mitosis
- Cloning
Mitosis Process
Process where a cell splits identically into 2 smaller cells with the same sub-cellular structure and grow
to become 2 identical (daughter) cells
Gametes
- Sex Cells (Sperm and Eggs) containing 23 single Chromosomes
- Gametes made my Meiosis, they all are different
Sexual Reproduction
- Involves fusion of Male and Female Gametes, this is Fertilisation
- Offspring has Genetic information from both parents, variation in offspring, variation important for long-term survival
Meiosis Process
- Takes place in Reproductive Organs, Testes/Ovaries
- Cell with 2 Sets of Chromosomes copied to become a Cell with 4 sets, halved 2 times into 4 single Chromosomes Cells called Gametes, genetically different
- 4 Gametes formed from 1 Cell
- Chromosomes are halved
Human Cells
- Contain 23 pairs of Chromosomes, which is genetic information
Fertilisation
- During Sexual Reproduction Gametes of both sexes fuse to create a normal human cell (23 Pairs from Chromosomes), variation in Chromosomes now
- Restores the Chromosomes lost in Meiosis
Mitosis in Fertilisation
- After human cell is created, Mitosis divides it into identical cells called Embryos
Embryos
Made from Mitosis during Fertilisation which develops and differentiates into other cell types: Nerve and Muscle cells to produce offspring
Allele
- Different versions of the same gene
- Allele are for phenotypes
Dominant and Recessive Alleles
- Dominant Allele rules over Recessive Allele
- In Punnet Square if there’s a gene with both Dominant and Recessive Allele its Heterozygous
- If same Allele then its Homozygous
Genome
All the DNA in an organism
Inheritance
Chromosomes in your carry DNA as genes, which have different variation (Alleles), which determine characteristics
Heterozygous
2 different alleles in a gene, Aa
Homozygous
Alleles in Gene are the same, AA or aa
Environment roles of Genetics
Depending on your lifestyle and surroundings, genes can change into something different despite your parents genes
Genotype
Mix up of Alleles for 1 characteristic, doesn’t have to be a physical, shown through letters representing the Allele, AA, Bb etc
Phenotype
Variable describing the Characteristic, such as Polydactyly, CF and Hair/Eye colour
Gene
Section of DNA
Sex Chromosomes
Males - XY Chromosomes
Females- XX Chromosomes
DNA Shape
2 strands of Polymer connected by genetic code (bases) forming the Double Helix
Cystic Fibrosis (CF)
- Inherited Recessive Disorder, lot of mucus is made
- Need 2x Recessive CF Alleles for a chance of inheriting it
- Caused by disorder of Cell Membranes
Polydactyly
- Growth of extra fingers/toes
- Cause by AT LEAST 1 dominant Polydactyly Allele
IVF
- Zygote, created in a lab, becomes a Embryo, inserted back into Uterus to grow into Foetus
- Embryo Screening can also take place
Embryo Screening
- Embryo’s Alleles can be examined if they are carriers of genetic disorders
- If Embryo is a carrier, it can be replaced
- Happens before Pregnancy
Advantages of Embryo Screening
- Low risk of miscarriage / abortion not needed
- Reduce healthcare costs, less disorderly people
- Suffering reduced, less people with health problems
Disadvantages of Embryo Screening
- Very Expensive
- Embryo’s can be discarded to find most desirable one with good Phenotypes, preference/prejudice
- Discarding Embryos is Unethical
