Answer the following question given this paragraph: Types of Receptors Receptors are protein molecules in the target cell or on its surface that bind ligand. There are two types of receptors, internal receptors and cell-surface receptors. Internal receptors Internal receptors, also known as intracellular or cytoplasmic receptors, are found in the cytoplasm of the cell and respond to hydrophobic ligand molecules that are able to travel across the plasma membrane. Once inside the cell, many of these molecules bind to proteins that act as regulators of mRNA synthesis (transcription) to mediate gene expression. Gene expression is the cellular process of transforming the information in a cell's DNA into a sequence of amino acids, which ultimately forms a protein. When the ligand binds to the internal receptor, a conformational change is triggered that exposes a DNA-binding site on the protein. The ligand-receptor complex moves into the nucleus, then binds to specific regulatory regions of the chromosomal DNA and promotes the initiation of transcription (Figure 9.4). Transcription is the process of copying the information in a cells DNA into a special form of RNA called messenger RNA (mRNA); the cell uses information in the mRNA (which moves out into the cytoplasm and associates with ribosomes) to link specific amino acids in the correct order, producing a protein. Internal receptors can directly influence gene expression without having to pass the signal on to other receptors or messengers. Q: What type of receptors, also known as intracellular or cytoplasmic receptors, are found in the cytoplasm of the cell and respond to hydrophobic ligand molecules that are able to travel across the plasma membrane? Choices: - external - essential - mechanical - internal A:
internal
Answer the following question given this paragraph: Prokaryotic cells are cells without a nucleus. Q: What term is used to describe cells without a nucleus? Choices: - Simple - unicellular - monophyletic - prokaryotic A:
prokaryotic
Q: Answer the following question given this paragraph: Aerobic respiration begins with the entry of the product of glycolysis, pyruvate, into the mitochondria. For each initial glucose molecules, two pyruvate molecules will enter the mitochondria. Pyruvate, however, is not the molecule that enters the Krebs cycle. Prior to entry into this cycle, pyruvate must be converted into a 2-carbon acetyl-CoenzymeA (acetyl-CoA) unit. The conversion of pyruvate into acetyl-CoA is referred to as the pyruvate dehydrogenase reaction. It is catalyzed by the pyruvate dehydrogenase complex. This process produces one NADH electron carrier while releasing a CO 2 molecule. This step is also known as the link reaction or transition step, as it links glycolysis and the Krebs cycle. Of course, as two pyruvates result from glycolysis, two acetyl-CoAs are produced as are 2 NADH molecules. Q: For each initial glucose molecules, two pyruvate molecules will enter where? Choices: - the plasma - the nucleus - Golgi apparatus - the mitochondria A:
A: the mitochondria
Question: Answer the following question given this paragraph: The largest, most complex covalent molecules have thousands of atoms. Examples include proteins and carbohydrates, which are compounds in living things. The smallest, simplest covalent compounds have molecules with just two atoms. An example is hydrogen chloride (HCl). It consists of one hydrogen atom and one chlorine atom, as you can see in the Figure below . You can watch an animation of hydrogen chloride forming at the following URL. Q: What type of compound is hydrogen chloride? Choices: - polar - metal - ionic - covalent A:
Answer: covalent
*Question*
Answer the following question given this paragraph: When acellular slime molds swarm, they fuse together to form a single cell with many nuclei. Q: When acellular slime molds swarm, they fuse together to form a single cell with many what? Choices: - digestive tracts - cytoplasm - lungs - nuclei A:
**Answer**
nuclei
*Question*
Answer the following question given this paragraph: First, plant cells have a large central vacuole that holds a mixture of water, nutrients, and wastes. A plant cell's vacuole can make up 90% of the cell's volume. The large central vacuole essentially stores water. In animal cells, vacuoles are much smaller. Q: What does the large central vacuole do? Choices: - use water - create glucose - heat water - store water A:
**Answer**
store water