Answer:
4. a
5. a
6. a
7. a
8. a
9. a
10. True
Explanation:
4. Units of inheritance in living organisms are known as genes. These genes exist in pairs in all organisms and a copy of each gene is passed down to the offspring during reproduction.
Correct option: a
5. Assuming the dominance of allele A over allele a:
AA x aa
Aa Aa Aa Aa
All the offspring will appear tall since the effects of allele a is masked by allele A.
Correct option: a
6. From the cross in (5) above, the genotypic ratio of the offspring is 100% Aa.
Correct option: a
7. Alternate forms of genes in living organisms are known as alleles. A copy of the alleles is usually passed down to the offspring during the process of reproduction.
Correct option: a
8. Phenotypes are the physical appearance of organisms. They are physical interpretation of genes.
Correct option: a
9. The law of segregation was postulated by Gregor Mendel. It states that gene pairs segregate during the process of meiosis and then randomly unite during the process of fertilization.
Correct option: a
10 Heterozygous organisms have two different alleles for the same genes. For genes that obey Mendelian laws, heterozygous condition is characterized by one dominant and one recessive alleles.
Answer:A. The release of calcium ions causes myosin and actin to attach to each other.
The contraction of skeletal muscles takes place by induction of a nerve impulse, which produces a movement and the interaction of the filaments containing proteins named as actin and myosin. This interaction of filaments is regulated by proteins called tropomyosin and troponin present on the actin filaments. The motor nerve causes the depolarization of the muscle membrane sarcolemma. This triggers the sarcoplasmic reticulum to release calcium ions. This calcium binds to troponin and thus allows the tropomyosine strand on the actin filament to displace so that the part of the actin where myosine head needs to be attached remain uncovered. Binding of the actin myosine filament results in contraction.
Hence, the release of calcium ions causes myosin and actin to attach to each other causes muscle contraction.
I can answer when you say if you are talking about cells or no
The nitrogenous base found in DNA but not RNA is called thymine. That's what it bonds to.
