Cell Biology

What is the fundamental unit of life? A - Water B - Phospholipids C - Fatty Acids D - Cells

D - Cells All living things on Earth are made up of one or more cells.

What are ribosomes comprised of? A - tRNA and protein B - mRNA and tRNA C - mRNA and protein D - rRNA and mRNA E - rRNA and protein

E - rRNA and protein

What is another term for the intracellular space? A - Cytoplasm B - Hydrophobic region C - Bilayer D - Phospholipids E - Cholesterol

A - Cytoplasm The CYTOPLASM is the intracellular space within the cell containing various cell structures and components.

Where can you NOT find ribosomes preforming translation? A - Smooth endoplasmic reticulum B - Cytoplasm C - Mitochondria D - Chloroplasts

A - Smooth endoplasmic reticulum

Which of the following does NOT take place in the nucleus? A - Ribosome synthesis B - All of these take place in the nucleus C - Transcription D - Replication

B - All of these take place in the nucleus

Active transport involves... A - Simple diffusion B - Chemical energy C - The movement of water D - Movement with a concentration gradient E - Sodium ions

B - Chemical energy

What language does the word 'hydro' come from? A - Russian B - Greek C - Persian D - Latin

B - Greek

Which types of molecules will easily pass through the fatty acid chains of the bilayer? A - Polar B - Hydrophobic C - Ions D - Hydrophilic

B - Hydrophobic

Which of the following is involved in cell communication? A - Cholesterol B - Integral proteins C - Phospholipids D - Carbohydrates E - Cytoplasm

B - Integral proteins INTEGRAL PROTEINS are membrane proteins that actually 'integrate' themselves throughout the bilayer, where they can cross both inside and outside of the cell. They have both hydrophilic and hydrophobic regions.

The ________ is a double membrane that shields the nucleus. A - DNA B - Nuclear envelope C - Chromatin D - Nucleolus

B - Nuclear envelope

Diffusion of small non-polar molecules across the cell membrane along a concentration gradient is... A - Channel B - Simple C - Osmosis D - Facilitated E - Active

B - Simple SIMPLE diffusion is the unassisted passage of small, hydrophobic, non-polar molecules from a higher concentration to a lower concentration.

A sodium potassium pump is a type of... A - Passive transport B - Triport C - Antiport D - Symport E - Uniport

C - Antiport

The Fluid Mosaic Model describes proteins... A - Tethered to one place in the membrane B - Bound to carbohydrates C - Floating laterally throughout the space D - As hydrophobic and hydrophilic molecules E - AS existing only on the cytoplasmic side of the cell

C - Floating laterally throughout the space

Which of the following is true of the lysosome? A - It pumps protons into the extracellular space B - It builds internal cellular structures and proteins C - It digest molecules from endocytosis D - It maintains a basic pH

C - It digest molecules from endocytosis LYSOSOMES are structures within the cell that contain digestive enzymes. The lysosome is acidic compared to the rest of the cell because integral proteins in the membrane surrounding the lysosomes pump protons into this space.

Where is the starting point of ribosome synthesis? A - Nuclear pore B - Nuclear envelope C - Nucleolus D - Nuclear localization signal E - Nuclear lamina

C - Nucleolus The NUCLEOLUS is an area of the nucleus that is the starting site of ribosomal synthesis from rRNA and proteins.

Which ribosomal site joins amino acids via a polypeptide bond? A - E site B - R site C - P site D - A site

C - P site The P site is where a polypeptide bond is formed between a new amino acid and the growing amino acid chain.

A foreign cell has entered your blood stream. Which process describes how it can be engulfed by one of the cells in your immune system? A - Pinocytosis B - Exocytosis C - Phagocytosis D - Receptor-mediated cytosis E - Lysosome

C - Phagocytosis PHAGOCYTOSIS is the process where large molecules or other cells are eaten by engulfing them. The cell membrane folds around the object, creating a vesicle that can be internalized.

How is the phospholipid bilayer oriented? A - One layer of phospholipids forms a circle B - Head and tails alternate directions within a layer C - Tails face inward towards each other D - One head layer touches the second tail layer E - Heads face inward towards each other

C - Tails face inward towards each other A phospholipid is made up of a phosphate group and lipid that are attached together by a glycerol group. The two lipid tails are made of hydrocarbon fatty acids bound to the glycerol by an ester linkage.

Carbohydrates in the cell membrane contribute to... A - Cell to cell adhesion B - Structure C - Protection D - Fluidity

CARBOHYDRATE chains can be found outside of the cell attached to lipids or proteins. They act as binding sites or can help cells adhere to other cells.

What is the purpose of cholesterol in the cell membrane? A - To help maintain fluidity B - To help cells stick together C - To make the bilayer hydrophobic D - To communicate with other cells

CHOLESTEROL floats throughout the bilayer. It is found within the hydrophobic tails where they help maintain membrane fluidity. It provides both structure and helps it act as a protective layer while keeping the membrane from freezing.

Chemical energy is required for active transport to establish a specific concentration gradient. In a sodium potassium pump, chemical energy specifically serves to help the pump... A - Create a symport B - Bind to the potassium ions C - Allow passive diffusion D - Change the shape E - All of these

D - Change the shape

What part of the a phospholipid is hydrophobic? A - The extracellular region B - Phosphate group C - The intracellular region D - Fatty acid chain

D - Fatty acid chain

The inside of a cell contains more solutes than the outside of the cell. Which describes the inside of the cell and the direction of water? A - Inside the cell is hypertonic. Water will move towards the outside of the cell B - Isotonic. Water will move in either direction C - Inside the cell is hypotonic. Water will move towards the outside of the cell D - Inside the cell is hypertonic. Water will move towards the inside of the cell. Inside the cell is hypotonic. Water will move towards the inside of the cell

D - Inside the cell is hypertonic. Water will move towards the inside of the cell. HYPERTONIC solutions have less solutes and more water. HYPERTONIC solutions have more solutes and less water. ISOTONIC solutions are even.

Exocytosis can be used to secrete newly made proteins out of the cell. It can also be used to add _____ directly to the cell membrane. A - Solutes B - Lysosomes C - Protons D - Integral membrane proteins

D - Integral membrane proteins

Which of the following is NOT true of the phosphate group in a phospholipid? The phosphate group is... A - Attached to fatty acids via a glycerol group B - Touching the insides of a cell C - Hydrophilic D - Positively charge E - Polar

D - Positively charge

Which of the following first binds to the mRNA message? A - Cytoplasm B - Rough endoplasmic reticulum C - Large subunit D - Small subunit E - P site

D - Small subunit The SMALL subunit recognizes and binds to a mRNA transcript.

This type of integral membrane protein moves two substances in the same direction. A - Carrier B - Triport C - Uniport D - Symport E - Antiport

D - Symport A SYMPORT is an integral membrane protein that moves two ions in the same direction. An ANTIPORT is an integral membrane protein that moves one ion or molecule in one directions while moving a second in the opposite direction.

What type of integral protein helps molecules move across the cell membrane by binding and releasing them? A - Hydrophobic B - Channel C - Pore D - Hydrophilic E - Carrier

E - Carrier

Where are the A, P, and E sites located? A - Small subunit B - rRNA C - Cytoplasm D - Rough endoplasmic reticulum E - Large subunit

E - Large subunit These are the three tRNA binding sites on the large subunit. The A site is the amino acid site, where a specific tRNA binds to a specific mRNA sequence. The E site is the exit site where the tRNA exits.

Which process best describes non-specific internalization of dissolved ions outside the cell? A - Lysosome B - Receptor-mediated endocytosis C - Phagocytosis D - Exocytosis E - Pinocytosis

E - Pinocytosis PINOCYTOSIS is the process where small, dissolved substances and liquids are taken up by a cell. This is similar to phagocytosis which engulfs large molecules

Which process best describes the internalization of a specific protein outside the cell? A - Lysosome B - Phagocytosis C - Exocytosis D - Pinocytosis E - Receptor-mediated endocytosis

E - Receptor-mediated endocytosis RECEPTOR-MEDIATED ENDOCYTOSIS is a process that recognizes and targets a specific substrate through the help of integral membrane proteins on the cell membrane surface.

Why does active transport require energy? A - To move solutes with a concentration gradient B - To transport small, hydrophobic molecules across the membrane C - To move solutes to an equal concentration inside and outside the cell D - To diffuse substances passively E - To move solutes against a concentration gradient

E - To move solutes against a concentration gradient

What type of transport uses membrane proteins to passively move solutes? A - Facilitated diffusion B - Simple diffusion C - Active transport D - Osmosis E - All of these

FACILITATED diffusion uses integral membrane proteins to help larger, charged, hydrophilic, and polar molecules across a concentration gradient. There are carrier proteins that bind a molecule to facilitate transport and channel proteins that create a passageway across the membrane.

What type of cell might have more smooth ER? A - Nerve B - Heart C - Liver D - Skin

NEEDS ANSWER

Which of the following is NOT true of the endomembrane system? A - Completely closed space with no openings B - Releases contents in vesicles C - Continuous part of the cell membrane D - Made of membrane E works together to make, modify, and package molecules

NEEDS ANSWER

How do large proteins enter the cell? A - With a nuclear localization signal B - By stretching the nuclear pore C - All of these D - With chemical energy E - Helped by an import protein

The NLS is a specialized amino acid sequence that allows larger proteins into the nucleus. If they have this they will then pass through import proteins, using chemical energy to cause the pore to stretch.

Which of the following helps maintain the shape of the nucleus? A - Nuclear localization signal B - Nuclear pore C - Nuclear envelope D - Nuclear lamina E - Nucleolus

The NUCLEAR LAMINA attaches the nuclear envelope and chromatin to help maintain the structure.