Leaving CERT Biology 2011

Photosynthesis is a process that occurs in the chloroplasts of plant cells. Chloroplasts contain chlorophyll, a green pigment that captures sunlight and converts it into chemical energy through photosynthesis. This process is essential for plants to produce glucose and oxygen, which are necessary for their growth and survival. Therefore, the statement "Photosynthesis takes place in the chloroplast of the plant cell" is true.

The sino-atrial node, also known as the pacemaker, is responsible for initiating the electrical impulses that regulate the heart's rhythm. It is located in the right atrium of the heart. This node sends electrical signals to the atria, causing them to contract and pump blood into the ventricles. From there, the electrical signals travel to the atrioventricular node, which then sends the signals to the ventricles, causing them to contract and pump blood out of the heart. Therefore, the statement "The sino-atrial node (pacemaker) is located on the right side of the heart" is true.

Around day 14 of the menstrual cycle, ovulation occurs. This is the process where a mature egg is released from the ovary and travels down the fallopian tube, making it available for fertilization by sperm. Ovulation is a crucial event in the menstrual cycle and is triggered by a surge in luteinizing hormone (LH) levels. It marks the peak of fertility and is an essential step in the reproductive process.

Phospholipids are a major component of cell membranes. They form a lipid bilayer structure, with the hydrophilic (water-loving) heads facing outward towards the aqueous environment and the hydrophobic (water-fearing) tails facing inward, creating a barrier that separates the cell's internal contents from the external environment. Therefore, it is expected to find phospholipids in the cell membrane.

The walls of xylem are reinforced with lignin, a hard material. Lignin provides strength and rigidity to the xylem cells, allowing them to withstand the pressure exerted by the movement of water and minerals through the plant. It also helps in preventing the collapse of xylem vessels, ensuring efficient water transport from the roots to the leaves.

Endosperm is a food reserve in some seeds, which means that it serves as a source of nutrients for the developing embryo. It is typically found in angiosperm seeds and provides essential nutrients such as carbohydrates, proteins, and lipids. This food reserve is crucial for the successful germination and early growth of the plant. Therefore, the statement "endosperm is a food reserve in some seeds" is true.

Lipase is an enzyme that plays a crucial role in the digestion of fats. It breaks down triglycerides into fatty acids and glycerol, allowing for their absorption and utilization by the body. Lipase is produced by the pancreas and is released into the small intestine, where it acts on dietary fats present in the food we consume. Without lipase, the digestion and absorption of fats would be impaired, leading to various digestive disorders and nutrient deficiencies.

FSH (follicle-stimulating hormone) and LH (luteinizing hormone) are both hormones that play a crucial role in regulating the female reproductive system. They are responsible for the development and release of eggs from the ovaries during the menstrual cycle. Therefore, both FSH and LH influence the ovaries, as they stimulate the growth of follicles within the ovaries, leading to ovulation and the release of mature eggs.

Under anaerobic conditions in a human muscle cell, pyruvate is converted into lactic acid. This process, known as anaerobic glycolysis, occurs when there is a lack of oxygen available for cellular respiration. Pyruvate is produced during the breakdown of glucose in glycolysis, and in the absence of oxygen, it is converted into lactic acid by the enzyme lactate dehydrogenase. This allows the muscle cell to continue producing ATP (energy) even without oxygen, but it also leads to the build-up of lactic acid, which can cause muscle fatigue and soreness.

The correct answer is lipid, fat, fatty acids, triglycerides, lipids. The small intestine is responsible for absorbing nutrients from the food we eat. Lipids, which include fats and fatty acids, are mainly absorbed into the lacteals or lymph in the small intestine. Triglycerides, which are a type of lipid, are broken down into fatty acids and glycerol during digestion and then absorbed into the lacteals or lymph. Therefore, all of the options provided - lipid, fat, fatty acids, triglycerides, lipids - are correct as they all represent the types of food mainly absorbed from the small intestine into the lacteals or lymph.

Biologists use the term "variation" to describe differences within a population with respect to features such as height. Variation refers to the range of differences that exist among individuals within a population, including differences in physical traits, genetic makeup, and behaviors. This variation is a fundamental concept in biology and plays a crucial role in understanding evolution, adaptation, and the diversity of life on Earth.

Mitosis in a single-celled organism serves the function of reproduction. During mitosis, the cell's nucleus divides into two identical nuclei, followed by the division of the cytoplasm, resulting in two genetically identical daughter cells. This process allows the single-celled organism to reproduce asexually, producing offspring that are genetically identical to the parent cell. Therefore, mitosis is crucial for the reproduction and propagation of single-celled organisms.

Respiration and digestion are examples of catabolic reactions. Catabolic reactions involve the breakdown of larger molecules into smaller ones, releasing energy in the process. Respiration is the process by which cells break down glucose to produce energy in the form of ATP. Digestion is the process by which food is broken down into smaller molecules that can be absorbed by the body. Both of these processes involve the breakdown of larger molecules into smaller ones, making them examples of catabolic reactions.

Ligaments do not join muscles to bones. Ligaments are tough bands of connective tissue that connect bones to other bones, providing stability and support to joints. On the other hand, tendons are the structures that connect muscles to bones, allowing for movement and transmitting the force generated by the muscles to the bones. Therefore, the statement is false.

The hepatic portal vein does not join the liver to the heart. Instead, it is responsible for carrying blood from the gastrointestinal tract, spleen, and pancreas to the liver. This blood contains nutrients and other substances that need to be processed by the liver before being distributed to the rest of the body. Once the blood has been filtered and processed by the liver, it is then sent back into circulation through the hepatic veins, which do not connect directly to the heart.

Light is not essential for the germination of seeds. While some seeds may require light for germination, many others do not. The germination process primarily depends on factors such as temperature, moisture, and oxygen availability. Some seeds even require darkness to germinate. Therefore, it is incorrect to say that light is essential for the germination of all seeds.

Under anaerobic conditions in a yeast cell, pyruvate is converted into ethanol. This process is known as fermentation. Pyruvate is first converted into acetaldehyde, which is then reduced to ethanol by the enzyme alcohol dehydrogenase. This fermentation pathway allows yeast cells to continue producing ATP in the absence of oxygen.

In dalmatian dogs, the allele for black spots is dominant while the allele for brown spots is recessive. Since both parents are heterozygous (Bb), they each carry one dominant allele for black spots and one recessive allele for brown spots. When these parents reproduce, there is a 25% chance that both parents will pass on their recessive brown allele (bb) to the offspring, resulting in brown spots. Conversely, there is a 75% chance that at least one parent will pass on the dominant black allele (B) to the offspring, resulting in black spots. Therefore, the % chance of obtaining offspring with black spots is 75%.

The second stage of respiration takes place in the mitochondrion. This is where the process of aerobic respiration occurs, specifically in the inner membrane of the mitochondrion. During this stage, glucose is broken down further to produce energy in the form of ATP through the citric acid cycle and the electron transport chain. The mitochondrion is often referred to as the "powerhouse" of the cell due to its crucial role in generating energy.

Urea is not formed in the kidneys. It is actually produced in the liver as a waste product when proteins are broken down. The kidneys then filter urea out of the blood and excrete it in the urine. Therefore, the statement that urea is formed in the kidneys is false.

Vitamins can be divided into two groups based on their solubility - water-soluble and fat-soluble. Water-soluble vitamins include vitamin C and the B vitamins, which are not stored in the body and need to be replenished regularly. Fat-soluble vitamins, on the other hand, include vitamins A, D, E, and K, which are stored in the body's fatty tissues and liver.

Carbohydrates consist of carbon, hydrogen, and oxygen atoms. The ratio of hydrogen to carbon in carbohydrates is 2:1, while the ratio of hydrogen to oxygen is also 2:1. This means that for every carbon atom, there are two hydrogen atoms, and for every oxygen atom, there are also two hydrogen atoms. Therefore, both options mentioned in the answer, Hydrogen:Carbon and Hydrogen:oxygen, are correct.