TAKS Checkpoint # 1

The molecule shown in the diagram is DNA. DNA is a double-stranded molecule that contains the genetic information of an organism. It is made up of nucleotides, which consist of a sugar, a phosphate group, and a nitrogenous base. The diagram likely represents the double helix structure of DNA, with the sugar-phosphate backbone and the nitrogenous bases (adenine, thymine, cytosine, and guanine) forming the rungs of the ladder. Cellulose is a polysaccharide found in plant cell walls, RNA is a single-stranded molecule involved in protein synthesis, and ATP is a molecule that provides energy for cellular processes.

Paper and cardboard would have the biggest impact on conserving trees if they were recycled. This is because paper and cardboard are made from trees, so by recycling them, we can reduce the need for cutting down more trees for paper production. Recycling paper and cardboard not only conserves trees but also saves energy and reduces greenhouse gas emissions associated with the production of new paper products.

Active transport is the correct answer because it is the process by which molecules are moved across the cell membrane against their concentration gradient, from an area of lower concentration to an area of higher concentration. Since the concentration of molecule X is greater inside the cell than outside, it suggests that the cell is actively transporting X against its concentration gradient to accumulate it inside the cell. Exocytosis involves the release of molecules from the cell, receptor proteins are involved in signal transduction, and second messengers are involved in intracellular signaling, but these processes do not explain the movement of X against its concentration gradient.

The molecule mentioned in the question is most likely referring to DNA, which is responsible for storing hereditary information. DNA carries the genetic instructions for the development, functioning, and reproduction of all known organisms. It contains the genes that determine an individual's traits and characteristics, and is passed down from one generation to the next. DNA is composed of nucleotides, which form the famous double helix structure, and its sequence of nucleotides is what encodes the hereditary information.

According to the chart, the category that makes up the greatest proportion of waste is "paper and cardboard". This can be inferred by analyzing the chart and observing that the bar representing paper and cardboard is the tallest, indicating that it has the highest weight compared to the other categories.

The Golgi Apparatus serves as the packaging and distribution center of a eukaryotic cell. It receives proteins and lipids from the endoplasmic reticulum, modifies them, and packages them into vesicles for transport to their final destinations within the cell or for secretion outside the cell. The Golgi Apparatus plays a crucial role in sorting, modifying, and packaging molecules, ensuring that they are correctly targeted and delivered to their intended locations.

Sodium chloride is an example of a compound because it is formed by the chemical combination of sodium and chlorine atoms. In a compound, two or more different elements are chemically bonded together in a fixed ratio. Sodium chloride is composed of sodium cations (Na+) and chloride anions (Cl-), which are attracted to each other by ionic bonds. This combination results in the formation of a new substance with unique properties different from its constituent elements.

Robert Hooke used a crude microscope to examine cork cells. Cork cells are the correct answer because Hooke is famously known for his discovery of cells in cork, which he observed under a microscope. This discovery led to the development of the cell theory, which states that all living organisms are composed of cells.

The features that are missing from this cell are the cell wall and chloroplast. The cell wall is a rigid structure that provides support and protection to plant cells, while chloroplasts are responsible for photosynthesis, the process that converts sunlight into energy. Without these features, the cell would not have the necessary support and would be unable to produce energy through photosynthesis.

In step B of the sodium-potassium pump, the substance that is released from the pump is the sodium ion. This is because the sodium-potassium pump actively transports three sodium ions out of the cell, while bringing two potassium ions into the cell. This process requires the hydrolysis of ATP, which provides the energy needed for the pump to function. Therefore, the correct answer is the sodium ion.

If a cell's sodium-potassium pumps do not function properly, the concentration of sodium ions inside the cell would increase. This would lead to an imbalance in the osmotic pressure, causing water to enter the cell by osmosis. As a result, the cell would swell and eventually burst.

In the given diagram of an animal cell, structures C and D are also found in prokaryotic cells. This is because prokaryotic cells, like animal cells, contain a cell membrane (structure C) that surrounds and protects the cell. Additionally, prokaryotic cells have a nucleoid (structure D), which is a region where genetic material is located. Therefore, structures C and D are common to both animal and prokaryotic cells.

A bacterium that has lost its flagella would be unable to move. Flagella are whip-like structures that bacteria use for locomotion. Without flagella, the bacterium would not be able to propel itself and therefore would be unable to move. The other options, such as dividing, maintaining its shape, and making proteins, are not directly related to the presence or absence of flagella.

The function of the structure labeled A is making ATP. ATP, or adenosine triphosphate, is the main energy currency of cells. It is produced during cellular respiration, specifically in the process called oxidative phosphorylation, which takes place in the mitochondria. Structure A is most likely referring to the mitochondria, as it is the organelle responsible for ATP production through cellular respiration.

Carboxypeptidase is an enzyme that specifically acts on proteins. It catalyzes the hydrolysis of peptide bonds at the C-terminal end of protein molecules, resulting in the release of individual amino acids. Therefore, the substrates of carboxypeptidase are proteins.

Facilitated diffusion is the process by which substances move across the cell membrane with the help of transport proteins. Unlike simple diffusion, facilitated diffusion requires the presence of specific protein channels or carriers. Among the given options, sugar is the only substance that requires facilitated diffusion to cross the cell membrane. Water can freely move through aquaporin channels, while sodium and chloride ions can pass through ion channels without the need for facilitated diffusion.

The dashed lines in the drawing represent hydrogen bonds. Hydrogen bonds are a type of intermolecular force that occurs when a hydrogen atom is attracted to an electronegative atom, such as nitrogen, oxygen, or fluorine. These bonds are weaker than covalent or ionic bonds but still play a significant role in determining the structure and properties of many molecules, such as DNA and proteins. Hydrogen bonds are important for maintaining the shape and stability of molecules and are crucial for many biological processes.

Yard waste can easily be recycled at home because it can be composted. Composting is a natural process in which yard waste, such as grass clippings, leaves, and branches, decompose and turn into nutrient-rich soil. This can be done in a backyard compost bin or pile, allowing homeowners to recycle their yard waste and use the resulting compost to enrich their gardens or lawns.

In this model, the correct statement about ion concentration is that Na+ ions collect outside the cell. This means that there is a higher concentration of Na+ ions outside the cell compared to inside.

Molecule X is a nucleotide because it contains a sugar and a phosphate group. Nucleotides are the building blocks of nucleic acids, such as DNA and RNA. They consist of a sugar molecule (ribose or deoxyribose), a phosphate group, and a nitrogenous base. The presence of both a sugar and a phosphate group in Molecule X suggests that it is a nucleotide.