That is true. Active transport goes against the concentration gradient. Particles want to move from higher concentration to lower concentration and even out, but active transport makes them move against that.
Answer:
The plasma membrane is selectively permeable
Explanation:
hydrophobic molecules and small polar molecules can diffuse through the lipid layer, but ions and large polar molecules cannot. Integral membrane proteins enable ions and large polar molecules to pass through the membrane by passive or active transport.
Answer:
Transcription and translation occur simultaneously in prokaryotes.
Explanation:
Prokaryotes lack membrane-bound organelles and therefore, do not have a nucleus. Transcription and translation occur in the cytoplasm. As soon as the required length of mRNA is being formed, ribosomes join it and start the process of translation. Prokaryotic genes lack introns. The primary transcript formed by transcription in prokaryotes does not undergo splicing.
On the other hand, the process of transcription occurs in the nucleus in eukaryotes while translation occurs in the cytoplasm. The primary transcript formed by transcription in eukaryotes undergoes modifications to remove introns and to add a poly-A tail and 5' cap. Post-transcriptional modifications and spatial separation of two processes in eukaryotes result in slower translation than prokaryotes.
Answer:
Protein is also used for growth and repair. Amid all these necessary functions, proteins also hold the potential to serve as a metabolic fuel source. Proteins are not stored for later use, so excess proteins must be converted into glucose or triglycerides, and used to supply energy or build energy reserves.
Answer:
r-selected species (e.g., American bullfrog)
Explanation:
The r-selected species (r-strategists) are those species in which their populations oscillate near the carrying capacity, i.e., the maximum population size sustained by a particular environment. These species are generally located in low-quality (less competitive) ecological niches and produce many offsprings that grow rapidly and have low chances of surviving to adulthood. Some examples of r-strategists include amphibians, fish, small mammals, etc. Conversely, K-selected species have more stable populations and produce a low amount of offspring (e.g., large mammals such as elephants).
