B13 Reproduction
- Created by: thenamewastske
- Created on: 27-10-22 16:14
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- B13 Reproduction
- 13.1 Types of reproduction
- asexual- one parent, cell division by mitosis, genetically identical, used for growth and repair
- sexual - 2 parents, cell division by meiosis, genetic info inherited from parents, variation
- 13.2 Cell division in sexual reproduction
- in meiosis, cell divides to form 2 chromatids and divides to from 4 gametes with half the no. of chromoso-mes
- when 2 gametes fuse, the zygote will have a full set of chromoso-mes
- in meiosis, cell divides to form 2 chromatids and divides to from 4 gametes with half the no. of chromoso-mes
- 13.3 Best of both worlds
- Fungi use asexual reproduction
- 2 hyphae (a mass of thin threads) from different fungi join and the nuclei fuse for two sets of chromosomes
- they undergo mitosis to make haploid spores with only one set of chromosomes
- Fungal spores made by mitosis are clones.
- 2 hyphae (a mass of thin threads) from different fungi join and the nuclei fuse for two sets of chromosomes
- malarial parasites reproduce asexually in blood cells
- when the mosquito bites the human, a temp drop occurs
- triggers sexual reproduction
- from a zygote and undergos meiosis to make new parasites
- triggers sexual reproduction
- when the mosquito bites the human, a temp drop occurs
- Fungi use asexual reproduction
- 13.4 DNA and the genome
- chromosomes made up of dna strands
- dna is a polymer with double helix structure
- genome is an organisms enitre genetic info
- genes are sections of dna that code for proteins
- chromosomes made up of dna strands
- 13.5 DNA structure and protein synthesis
- dna is made up of nucleotides
- made of a phospate, sugar and base
- bases A and T bond and C and G
- Adenine, Thymine, Cytosine, Guanine
- bases A and T bond and C and G
- made of a phospate, sugar and base
- genes produce a template which binds to a ribosome
- carrier molecules bind to amino acids and attach to the template
- when complete the chain folds up in a unique shape
- carrier molecules bind to amino acids and attach to the template
- dna is made up of nucleotides
- 13.6 Gene expression and mutation
- gene is expressed when it codes for a protein
- mutations are change in genetic material
- mutation in amino acids changes protein shape
- possibly losing its active site and unable to bind with substrate
- mutation in amino acids changes protein shape
- 13.7 Inheritance in action
- alleles are different versions of the same gene
- homozygous means identical
- heterozygous means 2 different
- alleles are different versions of the same gene
- 13.8 More about genetics
- male sex chromosomes are XY
- female sex chromosomes are **
- 13.9 Inherited disorders
- polydactyly causes extra finger or toe, caused by dominant allele
- purely cosmetic
- cystic fibrosis prevents movement or substances
- mucus becomes thick and clogs organs
- caused by recessive allele
- no cure
- treatment with antibiotics or physiotherapy
- polydactyly causes extra finger or toe, caused by dominant allele
- 13.10 Screening for genetic disorders
- cells from embryo must be harvested to screen
- amniocentes-is, 15-16 weeks
- takes amniotic fluid which has fetal cells
- chorionic vilus, 10-12 weeks
- takes tissue from placenta
- amniocentes-is, 15-16 weeks
- ivf isolates dna from embryo and tests it
- expensive and no cures for genetic disorders
- screening could result in 'designer babies'
- cells from embryo must be harvested to screen
- 13.1 Types of reproduction
- increase risk of miscarrige
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