B13 Flashcards
what is asexual reproduction
it does not involve the fusion of gametes
all genetic information comes from one parent
all the offspring are genetically identical to the parent
what is a clone
identical copies produced by asexual reproduction and are formed by mitosis
what is sexual reproduction
involves the fusion of gametes
there is a mixing of genetic information
variation in offspring
how are gametes formed
meiosis
what happens in meiosis
the chromosome number is halved
what is meiosis
the genetic material is copied before cell division and each chromosome forms two chromosomes
the cell divides twice
this forms four gametes each with a single set of chromosomes
all gametes are different
what are advantages of asexual reproduction
only one parent is needed
more time and energy efficient as individuals do not need to find a mate
faster than sexual reproduction
what are disadvantages of asexual reproduction
offspring are clones so little variation
if environmental conditions change all offspring are affected
what are advantages of sexual reproduction
produces variation
if the environment changes, variation gives a survival advantage by natural selection
what are disadvantages of sexual reproduction
two gametes are needed
takes time and energy to find a mate
often slower
what is an example of an organism that does both types of reproduction and how does it work
malarial parasites
asexual - in human host
sexual - mosquito
how do flowering plants reproduce asexually and sexually
asexual - many plants produce offspring by mitosis such as runners from strawberry plants
sexual - pollen and egg cells are made meiosis and fuse to form seeds
what is a gene
a small section of DNA on the chromosome
what does a gene do
has the code for a particular sequence of amino acids for a specific protein
what is a genome
the entire genetic material of that organism
how does knowing the human genome help scientists
search for genomes linked to different types of disease
understanding and treating inherited disorders
what are the long strands of DNA made from
chains of alternating sugar and phosphate sections
One of the bases is attached to each sugar
What is a nucleotide
each unit containing a sugar, phosphate and a base
what is a sequence of three bases a code for
a particular amino acid
what controls the order in which amino acids are joined together
the order of bases
