Quick bio! k12 !

a bat wing, an alligator leg, and a human arm are homologous structures. how does the presence of homologous structures support one aspect of the theory of evolution?

a. the fact that the bone structures are similar supports the theory that the animals shared a common ancestor.
b. the fact that the bone structures are similar supports the theory that all of the animals evolved from mammals.
c. the fact that the bone structures are completely different supports the theory that those organisms did not share a common ancestor.

an organism new to science was discovered during a recent underwater expedition to the great barrier reef in australia. the organism is multicellular, and its cells contain chloroplasts, a nucleus, and organelles. in which domain would a scientist place this organism?
a. bacteria
b. eukarya
c. archaea
d. animalia

which statement best describes the difference between the life cycles of plants and animals?
a. plants have a one-part life cycle and are entirely haploid; humans have a two-part life cycle, spending part of their life in a diploid phase and part in a haploid phase.
b.
plants have a one-part life cycle and are entirely diploid; humans spend their lives in a haploid phase.
c. plants have a two-part life cycle, spending part of their life in a diploid phase and part in a haploid phase; humans spend their lives in a diploid phase and produce gametes that are haploid.
d. different plants have a different number of phases in their life cycle; humans always have two phases in their life cycle.

what is the function of the human immune system?
a. to defend the body from invading pathogens
b. to regulate the production of hormones within the body
c. to produce red blood cells within bone marrow
d. to regulate enzymes involved in growth and development

plants and animals require energy to live. which statement best describes the difference between the way plants and animals obtain energy?
a. producers such as plants do not require a source of energy; animals must consume food for energy.
b. plants produce glucose that can be broken down by cellular respiration; animals digest foods to obtain glucose for use in cellular respiration.
c. plants produce atp during photosynthesis; animals produce atp during digestion.
d. both plants and animals absorb food from their surroundings.

1. The correct answer would be A. The fact that the bone structures are similar supports the theory that the animals shared a common ancestor.

Homologous structures refer to the organs or structures which are similar in structure but perform different functions as a result of adaptation towards different ecosystems.

2. The correct answer would be B. Eukarya

The organism contains a nucleus and other organelles including chloroplast. Thus, it can be correctly placed in Eukarya (eukaryotes).

3. The correct answer would be C. Plants have a two-part life cycle, spending part of their lives in a diploid phase and part in a haploid phase; humans spend their lives in a diploid phase and produce gametes that are haploid.

Plants usually show alternation of a generation that is, two-part life cycle. Humans do not show alternation of generation. They are diploid organisms which produce haploid gametes for reproduction.

4. The correct answer would be A. to defend the body from invading pathogens

The immune system is a defense system of our body. It protects our body from infections and toxins. It includes organs like thymus, lymph nodes, bone marrow et cetera.

5. The correct answer would be B. Plants produce glucose that can be broken down by cellular respiration; animals digest foods to obtain glucose for use in cellular respiration.

The energy demands of animals, as well as plants, are met by the process called cellular respiration. Glucose is the major substrate for this process. Plants are able to synthesize glucose through photosynthesis however, animals need to digest food to obtain glucose.

step 1: initiation

initiation is the beginning of transcription. it occurs when the enzyme rna polymerase binds to a region of a gene called the promoter. this signals the dna to unwind so the enzyme can ‘‘read’’ the bases in one of the dna strands. the enzyme is now ready to make a strand of mrna with a complementary sequence of bases.

step 2: elongation

elongation is the addition of nucleotides to the mrna strand. rna polymerase reads the unwound dna strand and builds the mrna molecule, using complementary base pairs. there is a brief time during this process when the newly formed rna is bound to the unwound dna. during this process, an adenine (a) in the dna binds to an uracil (u) in the rna.

step 3: termination

termination is the ending of transcription, and occurs when rna polymerase crosses a stop (termination) sequence in the gene. the mrna strand is complete, and it detaches from dna.

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