B13 - Reproduction Flashcards
D. Asexual reproduction
Involves one parent which produces a genetically identical clone by mitosis as there is no fusion of gametes.
D. Sexual reproduction
Involves the fusion of male and female gametes formed by meiosis
How many chromosomes does the zygote have?
46
Variation caused by?
In sexual reproduction there is a mixing of genetic information which leads to variation
D. Mitosis
Making identical two
D. Meiosis
Making eggs and sperm
Meiosis results in?
Sex cells called gametes which have half the original no. of chromosomes
Where are:
Female gametes made?
Male gametes made?
f- ovaries
m- testes
D. Haploid?
Half the usual number of chromosomes
D. Genome?
Entire genetic material of an organism
DNA is a …….
polymer
D. Gene?
Small section of DNA on a chromosome
D. Homozygote?
an individual with 2 identical alleles for a characteristic
D. Hetrozygote?
an individual with 2 different alleles for a characteristic
D. Genotype?
Alleles present or the genetic makeup of an individual, regarding a particular characteristic (eg. Bb or bb)
D. Phenotype?
describes the physical appearance of an individual regarding a particular characteristic (eg. black fur)
D. Dominant allele?
expressed in the phenotype, even if only one copy is present
Female sex chromosomes?
the same - XX
Male sex chromosomes?
Different - XY
Polydactyly?
Babies born with extra fingers or toes
What type of allele is polydactyly caused by?
dominant
What type of allele is cystic fibrosis caused by?
recessive
How does cystic fibrosis affect body?
- affects cell membranes - prevents movement of substances
- mucus becomes thick, so organs like lungs become clogged up
- pancreas cannot secrete enzymes properly because tubes blocked, so stunted growth
When is amniocentesis carried out?
15-16 weeks of pregnancy
Ways to test embryos for genetic diseases?
- amniocentesis
- chorionic villus sampling
How does chorionic villus sampling work?
small sample of placenta is taken at around 10-12 weeks to provide fetal cells to screen
How does amniocentesis work?
takes a sample of fluid from around fetus which contains fetal cells that can be screened