Cell Biology Quiz: Structure and Function

The main function of cells is to maintain proper homeostasis in the organism.

The two main types of cells are prokaryotic and eukaryotic.

The nucleus is separated from the cytoplasm by a nuclear membrane.

<p>The cell membrane consists of 50-55% lipids, 40-45% proteins, and 5-10% carbohydrates.</p> Signup and view all the answers

<p>The cell membrane is composed of a phospholipid bilayer, which has hydrophilic heads and hydrophobic tails.</p> Signup and view all the answers

<p>Integral proteins span the membrane and assist in transport, while peripheral proteins attach to the membrane's surface.</p> Signup and view all the answers

<p>Homeostasis refers to the maintenance of stable internal conditions within a cell or organism.</p> Signup and view all the answers

<p>The average thickness of the cell membrane is about 7.5 nm.</p> Signup and view all the answers

<p>Phospholipid molecules are arranged in two rows with hydrophobic ends lined up side by side, abutting each other, while the polar heads face outward.</p> Signup and view all the answers

<p>Only fat-soluble substances like oxygen, carbon dioxide, and alcohol can pass through due to the semi-permeable nature of the lipid layer.</p> Signup and view all the answers

<p>Integral membrane proteins traverse the membrane forming channels, while peripheral proteins are located outside the lipid bilayer but attached to polar heads.</p> Signup and view all the answers

<p>Cholesterol contributes to both lipid density and fluidity of the membrane.</p> Signup and view all the answers

<p>Carbohydrates form cell surface receptors that enable communication between the extracellular environment and the cell's interior.</p> Signup and view all the answers

<p>Endocytosis is a process where a large molecule enters the cell by the invagination of the plasma membrane, forming an endocytic vesicle.</p> Signup and view all the answers

<p>The lipid layer's semi-permeability means that gases and steroid hormones can pass freely, while other molecules need specific transport mechanisms.</p> Signup and view all the answers

<p>Glycoproteins and glycolipids are involved in forming cell surface receptors, facilitating communication and signaling between cells.</p> Signup and view all the answers

<p>Clathrin molecules guide receptor-mediated endocytosis by forming a coated pit on the inner side of the membrane.</p> Signup and view all the answers

<p>Phagocytosis is a type of endocytosis where immune cells engulf large molecules or cells, like bacteria, forming a phagosome.</p> Signup and view all the answers

<p>Pinocytosis involves the uptake of fluids and smaller molecules through the formation of pinocytic vesicles.</p> Signup and view all the answers

<p>Passive transport moves substances down the concentration gradient without energy, while active transport moves substances against the gradient using energy from ATP hydrolysis.</p> Signup and view all the answers

<p>The nucleus houses the cell's genetic material, DNA, which is organized into chromosomes.</p> Signup and view all the answers

<p>A kinetochore forms around the centromere, attaching chromosomes to the mitotic spindle fibers.</p> Signup and view all the answers

<p>Histones are basic proteins that form nucleosomes around which DNA is wrapped, facilitating the compaction of DNA into chromatin.</p> Signup and view all the answers

<p>DNA replication and RNA synthesis (transcription) occur within the nucleus during cell division.</p> Signup and view all the answers

<p>Lysosomes operate at a pH of about 4.5, which is significant because it enables the activation of acid hydrolase enzymes necessary for digestion.</p> Signup and view all the answers

<p>Lysosomal storage disorders are linked to defects in hydrolase enzymes, which hinder the breakdown and transport of smaller molecules from lysosomes to the cytoplasm.</p> Signup and view all the answers

<p>Peroxisomes are involved in various oxidation reactions and detoxify hydrogen peroxide by converting it to water and oxygen using the enzyme catalase.</p> Signup and view all the answers

<p>Plasmalogens are significant as they are a type of phospholipid crucial for the structure of plasma membranes in heart and brain cells.</p> Signup and view all the answers

<p>Mutations in peroxisomes can lead to cognitive impairment, developmental issues, intellectual disabilities, impaired vision and hearing, and liver failure.</p> Signup and view all the answers

<p>The cristae increase the surface area, enhancing the mitochondria's ability to generate ATP through oxidative phosphorylation.</p> Signup and view all the answers

<p>The mitochondrial matrix contains a gel-like fluid that houses various enzymes, calcium storage, mitochondrial DNA, and ribosomes.</p> Signup and view all the answers

<p>Transport vesicles carry newly synthesized and modified proteins from the Golgi complex to other locations within the cell.</p> Signup and view all the answers

<p>Lysosomes serve as the cell's digestive system, degrading external polymers and performing autophagy on worn-out organelles.</p> Signup and view all the answers

<p>Secretary vesicles are involved in secreting proteins and other substances outside the cell by fusing with the plasma membrane.</p> Signup and view all the answers

<p>The outer mitochondrial membrane is relatively permeable due to porin proteins, while the inner membrane is highly selective in its permeability.</p> Signup and view all the answers

<p>The mitochondrial matrix is involved in the initiation of programmed cell death, or apoptosis.</p> Signup and view all the answers

<p>Storage vesicles store specific molecules, such as neurotransmitters, until they are needed for release.</p> Signup and view all the answers

<p>The primary function of rough endoplasmic reticulum is protein synthesis.</p> Signup and view all the answers

<p>Smooth endoplasmic reticulum lacks ribosomes and is mainly composed of tubules, while rough ER has ribosomes and is composed of cisternae.</p> Signup and view all the answers

<p>The Golgi complex processes, modifies, and packages proteins synthesized in the endoplasmic reticulum.</p> Signup and view all the answers

<p>One important function of smooth endoplasmic reticulum is lipid synthesis, which is crucial for producing membranes and hormones.</p> Signup and view all the answers

<p>Mitochondria have a double membrane system and possess their own DNA, which is critical for energy production through ATP synthesis.</p> Signup and view all the answers

<p>The endoplasmic reticulum (ER) supplies proteins to the Golgi apparatus, where they are processed and packaged for transport.</p> Signup and view all the answers

<p>The two main types of endoplasmic reticulum are rough ER, which synthesizes proteins, and smooth ER, which synthesizes lipids.</p> Signup and view all the answers

<p>Mitochondria contribute to the endosymbiotic theory by demonstrating that they have their own DNA and can multiply independently through fission.</p> Signup and view all the answers