Karteikarten
Biology iGCSE - Topic 3 - Notes - Reproduction & Inheritance
Karten in diesem Stapel (30)
- 1•survival advantage •mate •extinct •parent •desirable characteristics •natural selection •variations •identical •selective breeding
- 2____ involves the fusion of a male and female gamete to produce a ____ that undergoes cell division and developed into an ____fertilisation
zygote
embryo - 3—
- 4—
- 5—
- 6What is GERMINATIONthe process in which seeds begin to develop into a new young plant
- 7What are the three elements needed to facilitate germination and whyWater: to activate enzymes to break down the starch food reserves in the seeds
Oxygen: for aerobic respiration to release energy for growth
Warmth: optimum temp for enzymes will increase growth rate - 8—
- 9—
- 10—
- 11—
- 12Secondary sexual characteristics Females: oestrogen Name 5 symptoms of oestrogen present in a femaleBreast development
Menstrual cycle begins
Growth of body hair
Widening of hips
Increased height - 13Secondary sexual characteristics Male: testosterone Name 5 symptoms of testosterone present in a maleGrowth of penis and testes
Production of sperm
Growth of facial and body hair
Muscle development
Voice lowering and breaking - 14Menstrual cycle The menstrual cycle lasts ____ days and the egg is usually released on day ____ (ovulation)28
14 - 15—
- 16Developing embryo The placenta allows diffusion of ___, ___ and ___ ___ from the mother's blood to the developing foetus of growth. ___ ___ and ___ from the foetus are passed into the mother's blood to be removed. It also takes one the production of ___glucose
oxygen
amino acids
carbon dioxide
urea
progesterone - 17What am I describing? An organism's reproductive cell (egg in female and sperm in males), which has half the number of chromosomes (23)Gamete
- 18What am I describing? The entire DNA of an organismgenome
- 19A structure found in the nucleus which is made up of a long strand of DNAChromosome
- 20—Gene
- 21The different forms of the gene - humans have two alleles for each gene as they inherit one from each parentAllele/variant
- 22Only one (out of two alleles) is needed for it to be expressed and for the corresponding phenotype to be observedDominant allele
- 23Two copies are needed for it to be expressed and for the corresponding the phenotype to be observedrecessive allele
- 24When both inherited alleles are the same (ie two dominant alleles or two recessive alleles)Homozygous
- 25When one of the inherited alleles is dominant and the other is recessiveHeterozygous
- 26The combination of alleles an individual has eg AaGenotype
- 27The physical characteristics that are observed in the individual eg eye colour. Phenotypic features are the result of polygenic (multiple genes) inheritance rather than single genesPhenotype
- 28When neither allele is dominant over the other, so both contribute to the phenotype eg. a white chicken and black chicken can have offspring that are speckled so the web is codominantCodominance
- 29—
- 30—
