Question

The human genome size is 3 billion base pairs, and the size of the baker's yeast genome, a single-celled organism, is 12 million base pairs. Therefore, the genome size for another single-celled organism, an amoeba a. is about the size of the human genome b. is about the size of the yeast genome c. is somewhere between the sizes of the yeast and human genomes d. cannot be predicted with any certainty

Short answer

The most reasonable answer is that the amoeba's genome size is somewhere between the sizes of the yeast and human genomes (option c). This option takes into account the potential variation in genome sizes among single-celled organisms without assuming that it must match another specific genome size exactly.

Step-by-step solution

Analyze option a

The first option suggests that the amoeba's genome size would be about the same as the human genome (3 billion base pairs). However, it's important to consider that humans are multicellular organisms and usually have larger genomes than most single-celled organisms, so this option is most likely not correct.

Analyze option b

The second option proposes that the amoeba's genome would be about the size of the yeast genome (12 million base pairs). While this may be more plausible than option a, as both yeasts and amoebae are single-celled organisms, it still doesn't account for the potential variation in genome sizes between different single-celled organisms.

Analyze option c

The third option implies that the amoeba's genome size would be somewhere between the sizes of the yeast and human genomes (between 12 million and 3 billion base pairs). This option seems more likely, as it recognizes that genome sizes for single-celled organisms could vary and that it doesn't necessarily have to match another known genome size exactly.

Analyze option d

The last option states that the amoeba's genome size cannot be predicted with any certainty. This option is also correct in the sense that we cannot precisely predict an organism's genome size without analyzing their individual genome. There is no given law that states how the genome size should behave among more or less related organisms.

Select the most reasonable answer

Considering all the options and the analysis performed previously, the most reasonable answer to this question is option: c. is somewhere between the sizes of the yeast and human genomes. This option is reasonable as it considers the potential wide range of genome sizes between different categories of organisms while still accounting for the fact that the genome sizes would not necessarily match exactly another known organism's genome size.

Key concepts

Genomics

Genomics is the branch of molecular biology concerned with the structure, function, evolution, and mapping of genomes. A genome comprises an organism's complete set of DNA, including all its genes, with human beings possessing approximately 3 billion base pairs in their DNA. Genomics includes the analysis of genome sequences to understand relationships among species, the functions of genes and non-coding sequences, and the heredity and variation of organisms.

Advancements in technologies such as DNA sequencing have revolutionized the field, allowing for genome size comparisons across different organisms, as in the textbook exercise. Genomes vary widely in size – some bacteria have less than a million base pairs while others, including humans, have genomes that reach into the billions. Understanding genome size and complexity not only is crucial for evolutionary biology but also has practical applications in medicine, agriculture, and biotechnology.

Single-celled Organisms

Single-celled organisms, also known as unicellular organisms, are living entities that consist of just one cell capable of performing all the functions necessary for life. This category includes bacteria, archaea, and many types of eukaryotes like the baker's yeast.

The genome sizes of single-celled organisms are incredibly diverse. For example, as noted in the exercise, the yeast genome comprises roughly 12 million base pairs. Despite their simplicity, some single-celled organisms have genome sizes that exceed those of more complex beings. For instance, certain amoebas have genomes much larger than yeast, showcasing that there is no strict correlation between organismal complexity and genome size. This variability anglicizes the prediction of the genome size for any given single-celled organism without specific genomic analysis.

Multicellular Organisms

In contrast to single-celled organisms, multicellular organisms are composed of multiple, specialized cells that work together to sustain life. This group includes plants, animals, and fungi, among other life forms. Human beings, representing the multicellular category, have a genome that is significantly larger than that of the single-celled baker's yeast, with approximately 3 billion base pairs.

Generally, multicellular organisms have more complex biological structures than unicellular organisms, which can result in larger genome sizes to support the additional complexity. However, this is not always the case—some multicellular organisms have relatively small genomes and vice versa. The size of a genome isn't always indicative of an organism's complexity, a concept highlighted by the vast range of genome sizes across different forms of life.