Chapter 2 Flashcards
DNA?
chemical substance that determines nature and function of each cell
Genes?
Basic unit of genetic information
Autosomes?
23 pairs of chromosomes, normal body cell
Allosomes?
Gamets- ovum and sperm and 23 chromosomes
Mitosis
cell replication, asexual
Meiosis
the process of the egg and sperm fermentation
Monozygotic Twins
Twins who are generally identical
-occurs from a cluster of cells splitting after fertilization
Dizygotic twins
Twins who are non identical
-two separate ova are fertilized by two separate sperms
What causes the sex of the child?
The sperm determines sex because xx is females and xy is male and the ovum will always be x and the sperm can be either x or y
Pea plant experiment(MENDEL)
planted yellow and green pea plants and discovered dominant and recessive traits.
Dominat is YY recessive is yy
Genotype vs Phenotype
Genotype is the coronation of genetic material and phenotype is what you can see.
Polygenic traits
Traits whose inheritance is controlled by multiple gene pairs
Homozygous vs heterozygous
homozygous is when a person receives the same allels YY heterozygous is when they have different allels Yy
Polygenic inheritance
The process of inheriting polygenic traits eg skin colour
Reaction range?
is the degree of variability in the expression of a trait depending on the environment.
Multifactorial transmission
process where traits are determined by both genetic factors and environmental factors.
Three stages of development?
1.germinal stage (0-2 weeks)
2.Embryonic stage (2-8 weeks)
3. Fetal stage (8weeks-birth)
What happens in germinal stage?
The zygote turns to a blastocyst and then implantation occurs. the umbilical cord and placenta start to form, the placenta develops from the mothers cells and the umbilical cord develops from the babies cells.
What happens in the embryonic stage?
organism is called an embryo and organs start to develope from three layers the endoderm, mesoderm and ectoderm. brain starts to show weak electrical activity. starts to resemble a person
The three layers in the embryonic stage.
endoderm develops digestive system and respiratory system, the mesoderm develops muscle bones and circulatory system, the ectoderm develops skin hair teeth and nervous system
What happenes in fetal stage?
The child is called a fetus and the organs become more developed and start working. The fetus can move.
