Biology 1113 - Homework Qs (Ch. 7 & 8)

What is the function of intermediate filaments?

** Anchorage of nucleus and other organelles ** Formation of nuclear lamina - Maintain cell shape by resisting tension (pull) (Serves only as a structural role - holds nucleus in place)

What is the function of microfilaments?

** Muscle contraction (move cells) ** Cell division (divide animal cells in two) - Maintain cell shape by resisting tension (pull) - Move organelles and cytoplasm in plants, fungi, & animals

What is the function of microtubules?

**Cell motility (via flagella or cilia) ** Move chromosomes during cell division - Maintain cell shape by resisting compression (push) - Assist formation of cell plate during plant cell division - Provide tracks for intracellular transport (Involved in cell structure, movement, and transport of materials within the cell - acts as the highway/motor proteins use this)

Leaf cells manufacture ATP and sugar. What organelle is most prominent in leaf cells?

Chloroplasts - they absorb light and manufacture sugar (photosynthesis) to be broken down in the mitochondria during cellular respiration

What are the functions of flagella and cilia?

Cilia and flagella are projections from the cell. They are made up of microtubules. They are motile and designed either to move the cell itself or to move substances over or around the cell. Cilia helps with rotational movement whereas flagella helps with wave-like movement (forward). Cilia are short and there are usually many (hundreds) cilia per cell. Flagella are longer and there are fewer flagella per cell (usually one to eight).

Parts of a prokaryotic cell

Cytoplasm, a singular circular chromosome located in the nucleoid, plasmids (supercoiled DNA molecules), ribosomes, cytoskeleton (a network of protein fibers), cell wall, plasma membrane

What type of organelle would be dominant in cells of your immune system that consume and digest bacterial cells?

Lysosomes - they digest and recycle components that are consumes (ex. bacteria)

Functions of the lysosomes

Macromolecule digestion , autophagy/phagocytosis/pinocytosis

What are the subunits of microfilaments? of intermediate filaments? of microtubules?

Microfilaments: actin Intermediate filaments: keratins, lamina, or other structural proteins Microtubules: alpha- and beta-tubulin dimers

Cardiac muscle cells use ATP to generate heartbeats. What organelle is most prominent in cardiac muscle cells?

Mitochondria - Uses stored energy in sugars to produce ATP for the heart to beat

Functions of the Golgi Apparatus

Modifies and sorts proteins from rough ER (adds molecular tags to proteins bound for secretion), cisternal maturation - Made up of cisternae (stacks of membranous sacs that are not physically connected)

Function of the rough ER

Protein synthesis (for secretion out of cell)

What is the function of the central vacuole?

Regulates cytoplasm composition, creates internal pressure, and stores cell compounds

Pancreatic cells secrete and export digestive enzymes. What organelle is most prominent in pancreatic cells?

Rough ER - manufactures and secretes digestive enzymes

Why should you expect an increased Golgi apparatus in addition to copious rough ER in a secretory cell (ex. in a pancreatic cell)?

Secretory cells (like pancreatic cells) have an increased amount of rough ER and Golgi because most of the proteins would be made in the rough ER (secretory proteins) and then they're passed through the Golgi before secretion

Testis cells export lipid-soluble signals. They produce testosterone (a steroid). What organelle is most prominent in testis cells?

Smooth ER - synthesizes lipids like testosterone

Parts of the endomembrane system

Smooth ER, rough ER, lysosomes, Golgi apparatus

Functions of the smooth ER

Synthesizes lipids, metabolizes carbohydrates, stores calcium ions (cell signaling), detoxifies drugs and poisons (enzymes are located here to break them down)

What is the function of the centriole?

The main function of the centriole is to help with cell division in animal cells. The centrioles help in the formation of the spindle fibers that separate the chromosomes during cell division (mitosis). Found in animal cells only (not plant cells). Made up of a protein called tubulin.

What is the fate of the phosphate group that is removed when ATP is converted to ADP? a) It is acquired by a reactant in an endergonic reaction. b) It is broken down into one phosphorus and four oxygen atoms. c) It is acquired by a reactant in an exergonic reaction. d) It is acquired by a reactant in a spontaneous reaction. e) It is used to convert an ATP into an AQP.

a) It is acquired by a reactant in an endergonic reaction. (By acquiring the phosphate group the reactant acquires energy.)

Which of these organelles produces H2O2 as a by-product? a) peroxisome b) nucleus c) mitochondrion d) flagellum e) centrioles

a) Peroxisome (Peroxisomes have two functions: break down fatty acids to be used for forming membranes and as fuel for respiration; and transfer hydrogen from compounds to oxygen to create hydrogen peroxide and then convert hydrogen peroxide into water. Peroxisomes are membrane bound and contain enzymes crucial for metabolic activity. Site of redox reactions)

_____ are the sites of protein synthesis. a) Ribosomes b) Peroxisomes c) Mitochondria d) Microfilaments e) Golgi apparatuses

a) Ribosomes

What are three attributes of mitochondria and chloroplasts that suggest they were once free-living bacteria? a) They have their own small, often circular chromosomes; they produce their own ribosomes; and they replicate independently of cellular division. b) They have an internal membranous system, they maintain chemical gradients across the outer membrane, and they have unique coloration when looked at under a microscope. c) They use oxygen to generate ATP, they use light to carry out electrochemical reactions, and they are contained within the larger cell. d) They do not undergo mitosis, they have a membrane surrounding the organelle, and they use ATP.

a) They have their own small, often circular chromosomes; they produce their own ribosomes; and they replicate independently of cellular division.

The nuclear lamina is an array of filaments on the inner side of the nuclear membrane. If a method were found that could cause the lamina to fall into disarray, what would you most likely expect to be the immediate consequence? a) a change in the shape of the nucleus b) inability of the ribosomes to produce proteins c) failure of chromosomes to carry genetic information d) the loss of all nuclear function e) the inability of the nucleus to divide during cell division

a) a change in the shape of the nucleus

The reaction ADP + P --> ATP is a(n) _____ reaction. a) endergonic b) exergonic c) spontaneous d) chemical e) hydrolysis

a) endergonic

Where are proteins produced other than on ribosomes free in the cytosol or ribosomes attached to the ER? a) in mitochondria b) in the Golgi apparatus c) in the nucleolus d) in the extracellular matrix e) in lysosomes

a) in mitochondria (By far the majority of mitochondrial proteins, about 99%, are made outside the mitochondria in the cellular cytoplasm. Present-day mitochondria do synthesize a few of their own proteins to upkeep the small percentage of internal mitochondrial proteins)

A white blood cell engulfing a bacterium is an example of _____. a) phagocytosis b) receptor-mediated endocytosis c) pinocytosis d) exocytosis e) facilitated diffusion

a) phagocytosis (Phagocytosis = "cell eating")

An organism with a cell wall would most likely be unable to take in materials through ________. a) phagocytosis b) active transport c) facilitated diffusion d) diffusion e) osmosis

a) phagocytosis (The cell wall is rigid and thick - cannot bend/move)

What is energy coupling? a) the use of energy released from an exergonic reaction to drive an endergonic reaction b) the hydrolysis of ATP to ADP + P c) a description of the energetic relationship between the reactants and products in an exergonic reaction d) a barrier to the initiation of a reaction e) the use of an enzyme to reduce EA

a) the use of energy released from an exergonic reaction to drive an endergonic reaction

In plant cells, why are toxins like nicotine, cocaine, and caffeine stored in vacuoles instead of the cytosol? a) The high concentration of toxins in vacuoles allows them to function more efficiently within the cell. b) Toxins in vacuoles are sequestered from the rest of the cell, where they could do harm. c) Toxins are degraded in the vacuoles, preventing them from harming the cell. d) Toxins are synthesized in the vacuoles.

b) (Vacuoles serve as storage depots that keep noxious compounds like toxins separate from the rest of the cell. If released into the cytosol, toxins would poison the cell)

In cells, what is usually the immediate source of energy for an endergonic reaction? a) glucose b) ATP c) as spontaneous reactions, endergonic reactions do not need an addition of energy d) sugar e) ADP

b) ATP (The hydrolysis of ATP provides the energy needed for an endergonic reaction)

_____ is/are identical in structure to centrioles. a) Mitochondria b) Basal bodies c) Microfilaments d) Chromatin e) Nuclear envelopes

b) Basal bodies (The main function of the centriole is to help with cell division in animal cells. The centrioles help in the formation of the spindle fibers that separate the chromosomes during cell division (mitosis). Centrioles are only found in animal cells. All centrioles are made of protein strands called microtubules. A basal body is a protein structure found at the base of a eukaryotic undulipodium (cilium or flagellum). The basal body serves as a nucleation site for the growth of the axoneme microtubules)

Ribosomal subunits are manufactured by the _____. a) lysosome b) nucleolus c) smooth endoplasmic reticulum d) peroxisome e) rough endoplasmic reticulum

b) Nucleolus (The nucleolus makes ribosomal subunits from proteins and ribosomal RNA, also known as rRNA. It then sends the subunits out to the rest of the cell where they combine into complete ribosomes. <- makes the parts of a ribosome)

Which of these organelles manufactures proteins bound for secretion out of the cell? a) nucleolus b) rough endoplasmic reticulum c) lysosomes d) Golgi apparatus

b) Rough Endoplasmic Reticulum (Ribosomes make (free) proteins to be used inside the cell, where as the rough ER makes secretory proteins bound for the exterior of the cell. Further processing and packaging occurs in the Golgi apparatus.)

Which organelle often takes up much of the volume of a plant cell? a) peroxisome b) vacuole c) Golgi apparatus d) lysosome e) mitochondrion

b) Vacuole

The energy for an endergonic reaction comes from a(n) _____ reaction. a) anabolic b) exergonic c) glucose + glucose --> maltose d) synthesis e) ADP + P --> ATP

b) exergonic (The energy released by an exergonic reaction can be used to drive an endergonic reaction)

The liver is involved in detoxification of many poisons and drugs. Which of the following structures is primarily involved in this process and, therefore, abundant in liver cells? a) rough ER b) smooth ER c) nuclear envelope d) transport vesicles e) Golgi apparatus

b) smooth ER

All proteins are synthesized by ribosomes in the cell. Some ribosomes float freely in the cytosol, while others are bound to the surface of the endoplasmic reticulum. Most proteins made by free ribosomes function in the cytosol. Proteins made by bound ribosomes either function within the endomembrane system or pass through it and are secreted from the cell.Which of the following proteins are synthesized by bound ribosomes? a) ribosomal protein b) insulin c) lysosomal enzyme d) actin e) DNA polymerase f) ER protein

b), c), and f) (Most proteins that function in the cytosol (such as actin) or in the nucleus (such as DNA polymerase) are synthesized by free ribosomes. Proteins that function within the endomembrane system (such as lysosomal enzymes) or those that are destined for secretion from the cell (such as insulin) are synthesized by bound ribosomes. As a protein destined for the endomembrane system is being synthesized by a ribosome, the first amino acids in the growing polypeptide chain act as a signal sequence. That signal sequence ensures that the ribosome binds to the outer membrane of the ER and that the protein enters the ER lumen)

The _____ is composed of DNA and protein a) centriole b) flagellum c) chromatin d) mitochondrion e) ribosome

c) Chromatin (Chromatin is a complex of DNA and protein found in eukaryotic cells. Its primary function is packaging long DNA molecules into more compact, denser structures.)

The _____ is a selective barrier, regulating the passage of material into and out of the cell. a) nuclear envelope b) lysosome c) plasma membrane d) chloroplast e) nucleus

c) Plasma membrane (The plasma membrane regulates the passage of material into and out of the cell)

Why would a small protein have an NLS, when it naturally diffuses across the nuclear pore complex without one? a) The NLS will be used to passively import the protein into the nucleus, without using energy. b) The NLS will be used to stimulate transcription in the nucleus. c) The NLS will be used to actively import the protein into the nucleus, leaving very little of the protein in the cytoplasm. d) The NLS will be used to control protein that diffuses across the pore, leaving the great amount of the protein in the cytoplasm.

c) The NLS will be used to actively import the protein into the nucleus, leaving very little of the protein in the cytoplasm.

Suppose a young boy is always tired and fatigued, suffering from a metabolic disease. Which of the following organelles is most likely involved in this disease? a) ribosomes b) lysosomes c) mitochondria d) Golgi apparatus

c) mitochondria (The most prominent roles of mitochondria are to produce the energy currency of the cell, ATP (i.e., phosphorylation of ADP), through respiration, and to regulate cellular metabolism.)

Suppose a cell has the following molecules and structures: enzymes, DNA, ribosomes, plasma membrane, and mitochondria. It could be a cell from _____. a) a plant but not an animal b) bacterium c) nearly any eukaryotic organism d) any kind of prokaryotic organism e) an animal but not a plant

c) nearly any eukaryotic organism (bacteria and prokaryotes do not have membrane-bound organelles like mitochondria. They produce ATP on the surface of the cell)

Chemical energy is a form of _____ energy. a) kinetic b) motion c) potential d) entropic e) heat

c) potential

You can recognize the process of pinocytosis when _____. a) a receptor protein is involved b) the cell is engulfing a large particle c) the cell is engulfing extracellular fluid

c) the cell is engulfing extracellular fluid (Pinocytosis = "cell drinking")

Eukaryotic cells manufacture cytoskeletal proteins, which help to maintain cell shapes and functions. What would you predict about these proteins? a) They travel to the nucleus in a transport vesicle with a specific signal. b) They are glycosylated in the Golgi apparatus. c) They initially contain signal sequences that allow their entrance into the endoplasmic reticulum. d) They are manufactured on free ribosomes in the cytoplasm.

d) They are manufactured on free ribosomes in the cytoplasm

Which of these reactions requires a net input of energy from its surroundings? a) catabolic b) hydrolysis c) exergonic d) endergonic e) ATP --> ADP + P

d) endergonic

Which of these are by-products of cellular respiration? a) ATP and carbon dioxide b) ATP, carbon dioxide, and water c) glucose, carbon dioxide, and water d) heat, carbon dioxide, and water e) carbon dioxide and water

d) heat, carbon dioxide, and water (ATP is a product, but it isn't a by-product)

Endocytosis moves materials _____ a cell via _____. a) out of ... membranous vesicles b) into ... a transport protein c) into ... facilitated diffusion d) into ... membranous vesicles e) out of ... diffusion

d) into... membranous vesicles

When chemical, transport, or mechanical work is done by an organism, what happens to the heat generated? a) It is used to store energy as more ATP. b) It is used to generate ADP from nucleotide precursors. c) It is transported to specific organs such as the brain. d) It is used to power yet more cellular work. e) It is lost to the environment.

e) It is lost to the environment

Which of these are hollow rods that shape and support the cell? a) peroxisomes b) chloroplasts c) plasma membrane d) microfilaments e) microtubules

e) Microtubules (Microtubules are rods that also play a role in organelle movement)

Where is calcium stored? a) microtubules b) rough endoplasmic reticulum c) mitochondria d) centrioles e) smooth endoplasmic reticulum

e) Smooth Endoplasmic Reticulum (In addition to storing calcium, the smooth ER also plays a role in detoxification and lipid synthesis)