Ch 4 Genetics Flashcards
what is genetics
the study of how characteristics are passed on from one generation to another
what are the two types of characteristics
inherited characteristics- characteristic you get from your parents
acquired characteristics- characteristics you learn through life
what are chromosomes
thread like structures found in the nucleus of a cell made up of protein and DNA
what a gene
a short strand of DNA within the chromosomes
how many genes in each cell in the human body
20,500
how many chromosomes in every human body cell
46
what is a gamete and how many chromosomes does it have
Gametes are the cells involved in reproduction. they have 23 chromosomes
male gamete- sperm
female gamete- egg
what is fertilization
when the male and female gametes fuse together to form a zygote
what are dominant and recessive genes
the dominant gene is the stronger gene
the recessive gene is the weaker gene
what is variation
all the differences in traits amongst members of the same species
what is a species
a group of organisms that can breed with each other and produce fertile offspring
what is variation caused by
inheritance and environment
what is natural selection
the process by which members of a species who are best suited to their environment are most likely to survive and reproduce
what is evolution
evolution is the gradual change of inherited characteristics of a species over a long period of time
what is artificial selection
changing organisms through breeding to improve their useful characteristics e.g. racehorses
what is mutation
a change in the gene or chromosome
what are three causes of mutation
smoking, exposure to UV rays, exposure to X rays
what a mutagen
an environmental factor that increases the risk of a mutation
how is down syndrome
caused
if a zygote receives the wrong number of chromosomes from a gamete
what is biotechnology
the use of living things to produce products and services
what is genetic engineering
changing the genes to produce desirable characteristics e.g. golden rice and insulin
