Answer:
Explanation:
A gene can be turned on or off by environmental factors or from other cells that activate proteins known as transcription factors.
A cell is the smallest basic unit of life
Answer:
to contract a muscle, myosin and actin filaments shorten, requiring ATP binding and hydrolysis
Explanation:
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Darwin's theory of evolution by natural selection can explain how antibiotics are becoming defective because the bacteria that is trying to be fought off might have had a mutation making it more likely to survive. Once that surviving bacteria makes offspring most of the first generation will die from the antibiotic but soon all of their offspring will produce a resistance to that antibiotic.
The male
human has a sperm cell and the female has an egg cell. The cells from the male
and female that combine to form a zygote are called gametes. The human sperm
and egg cells each contain 23 chromosomes. . A combination of gametes forms a
zygote with 46 chromosomes. The type of cell division that produces gametes
with half the normal chromosome number is the meiosis. Meiosis is the type of
cell division used in sexual reproduction. It will occur in the testes and
ovaries.<span>Chromosomes get
shuffled when eggs and sperm are made. Though most adult cells contain two sets
of chromosomes, sperm and egg cells are different. These special cells have
just one chromosome from each pair. Which chromosome they get from each pair is
random, making each sperm or egg cell unique. There is also a bit of mixing
before the chromosomes are sorted into individual sperm or egg cells.
Chromosomes from each pair in a mother or father, respectively, make contact
and exchange pieces of DNA, creating hybrid chromosomes. </span>