Cellular Foundations of Life

Question 1

Why is it important for a cell to have a semipermeable cell membrane?

Answer 1

The cell membrane is semipermeable to allow the cell to adapt to its environment, and also allows molecules to come in and out of the cell

Question 2

What is the most important building block of a membrane?

Answer 2

The phospholipid bilayer

Question 3

Which part of the cell is hydrophilic and faces the exterior and which part is hydrophobic and faces the interior?

Answer 3

the hydrophilic head is water loving and faces the outside of the membrane. The hydrophobic tails face the interior because they are fatty acids and dont like water

Question 4

Are glycoproteins and glycolipids more likely located on the outer surface or the inner surface membrane?

Answer 4

outer surface

Question 5

What is the function of the phospholipid bilayer membrane?

Answer 5

maintains structural integrity between inside and outside the cell

Question 6

What role does cholesterol serve in a cell membrane?

Answer 6

maintaining membrane fluidity

Question 7

oxygen is able to rapidly diffuse across cell membranes because its

Answer 7

small and nonpolar

Question 8

simple diffusion of water is slower because it is

Answer 8

passive

Question 9

facilitated diffusion allows water to cross membranes more quickly via

Answer 9

transmembrane and lipid-based

Question 10

Steroid hormones like testosterone are large and need a transport protein to cross the cell membrane. This is because they are

Answer 10

nonpolar and lipid-based

Question 11

simple and facilitated diffusion are examples of

Answer 11

passive transport

Question 12

Which type of protein forms a pore that allows small molecules such as water to cross the membrane?

Answer 12

channel protein

Question 13

how do carrier proteins work?

Answer 13

carrier proteins accept a molecule on one side of the cell, then the protein changes its shape as the molecule passes through the membrane, then releases the molecule on the membrane

Question 14

what is the difference between active and passive transport?

Answer 14

passive transport does not require energy while active does

Question 15

Why does the Na+/K+ pump require energy to operate and what provides this energy?

Answer 15

the pump requires energy because it is moving ions against their concentration gradient and the energy is provided by the hydrolysis of ATP

Question 16

What specifically is the Na+/K+ pump moving in and out of the cell?

Answer 16

3 Na out and 2 K in

Question 17

Cells require a different electrical charge across the inside and outside of their cell membrane. this differential charge is called the

Answer 17

resting membrane potential

Question 18

the central dogma is the process whereby

Answer 18

DNA makes RNA makes protein

Question 19

what are transcription factors?

Answer 19

proteins

Question 20

what do transcription factors do?

Answer 20

essential for gene expression and transcription

Question 21

what organelle is responsible for making proteins

Answer 21

ribosome

Question 22

the majority of cells in the pancreas have abundant rough ER. what is the most likely primary function of a cell with abundant rough ER?

Answer 22

protein production and secretion

Question 23

A cell has abundant smooth ER. What is the most likely function of a cell with abundant smooth ER?

Answer 23

synthesis of lipids for steroid hormone production

Question 24

Why are ribosome clinically important?

Answer 24

ribosomes are a target of many antibacterial drugs

Question 25

Sodium and potassium are important electrolytes in the body. What are the 2 ways that they can cross the cells membrane to enter a cell?

Answer 25

sodium/potassium pumps and ion channels

Question 26

which components are the main facilitators of transport across the cell membrane?

Answer 26

proteins

Question 27

Oxygen therapy is often provided to animals that are having difficulty breathing. Inhaled oxygen is quickly absorbed from an animal’s lungs into the blood stream. This is because it can easily diffuse down its concentration gradient. Why can oxygen easily diffuse across the cell membrane?

Answer 27

it is small and non-polar

Question 28

what term best describes the process of making mRNA from DNA?

Answer 28

transcription

Question 29

which organelle is responsible for breaking down and recycling aged cellular components?

Answer 29

lysosome

Question 30

Plasma cells are a type of white blood cell that can be identified by the position of their nucleus, which is usually pushed to one side rather than being centrally located. Plasma cells are also recognizable because of the pale zone around their nucleus, which is known as the ‘perinuclear halo’ (black arrow). Which organelle creates the effect of the perinuclear halo?

Answer 30

the golgi apparatus, which is packaging proteins