Answer:
Adaptations develop from variations within a population and help organisms to survive in their given environment. Changes in populations accumulate over time; this is called evolution. The fossil record shows us that present-day life forms evolved from earlier different life forms.
Answer:
mitochondria and chloroplasts
Explanation:
the theory says that the bacteria which used oxygen and changed it to ATP molecules changed into mitochondria and those that used light energy to manufacture their own food changed into chloroplasts.this happened after the small prokaryotes which were bacteria were engulfed by the bigger prokaryotes of which some managed to survive and lived together through symbiosis hence the evolution to mitochondria and chloroplasts creating a eukaryotic cell.
Answer:
True statements about transcription:
- Occurs in the nucleus
- Produces single-stranded mRNA using the antisense DNA strand as a template
- Precedes 5' capping and polyadenylation.
Explanation:
Transcription is the process by which a specific fragment of DNA (e.g., a gene) is used as template to synthesize a complementary RNA sequence, usually a messenger RNA (mRNA) molecule, which is then used to synthesize a protein in the ribosomes by a process called 'translation'. In eukaryotic cells, transcription occurs within the cell nucleus which contains the genetic material of the cell. Transcription factors are proteins that bind to DNA regulatory elements (e.g., promoter sequences) located at the 5′ end of the transcription initiation site and thus stimulate transcription. Both mRNA capping (5' cap) and polyadenylation are post-transcriptional modifications that serve to protect the nascent mRNA from enzymatic degradation and help in ribosome binding during translation.
Each cell in the human body contains about 25,000 to 35,000 genes.
