E3: The Chemistry of Life

Question 1

It is defined as the maintenance of a stable internal environment

Answer 1

Homeostasis

Question 2

In order to maintain homeostasis, cells continually transport substances in and out across the

Answer 2

Cell (plasma) membrane

Question 3

It is the cellular structure that regulates the transport of materials into and out of the cell

Answer 3

Cell membrane

Question 4

Architecture of the cell membrane allows certain molecules to pass through while keeping others out

Answer 4

Lipid bilayer

Question 5

Cell membrane is __________

Answer 5

Selectively permeable

Question 6

It is defined as the net movement of molecules or ions from a region of high concentration to a region of lower concentration

Answer 6

Diffusion

Question 7

Diffusion continues until a ________ is reached, which means that the molecules are randomly distributed throughout the system

Answer 7

State of equilibrium

Question 8

It is considered a form of passive transport because no energy is required in the process

Answer 8

Diffusion

Question 9

True or False

Diffusion can occur in a gas, a liquid, or a solid medium.

Answer 9

True

Question 10

True or False

Diffusion also occurs across the selectively permeable membranes of cells.

Answer 10

True

Question 11

All molecules possess _______ which provides the force for movement

Answer 11

Kinetic energy

Question 12

True or False

The fewer molecules in an environment, the higher the concentration of molecules, the lower the frequency of molecular collisions, and the slower the speed of diffusion.

Answer 12

False: The more molecules in an environment, the higher the concentration of molecules, the higher the frequency of molecular collisions, and the faster the speed of diffusion.

Question 13

What are the factors that affect rate of diffusion in the cell?

Answer 13

1. Temperature
2. Concentration gradient
3. Medium molecules diffuse in (gas, liquid, solid)
4. Molecular weight of the molecule
5. Charge
6. Solubility

Question 14

Cells acquire the molecules and ions they need from the?

Answer 14

Surrounding extracellular fluid

Question 15

True or False

In living cells, the ability of a molecule to cross the cell membrane is influenced by its shape, molecular weight, medium, and other characteristics.

Answer 15

False: In living cells, the ability of a molecule to cross the cell membrane is influenced by its size, charge, lipid solubility, and other characteristics.

Question 16

What are the small molecules that easily cross the membrane by passive transport processes that do not require energy?

Answer 16

1. Water
2. Oxygen
3. Amino acids
4. Ions

Question 17

Other molecules do not easily fit through the ____ and the cell must expend energy to bring them across

Answer 17

Lipid bilayer

Question 18

It is a special case of diffusion in which water molecules pass through a selectively permeable membrane, but larger molecules do not

Answer 18

Osmosis

Question 19

Proceeds from a region of high-water concentration, across a semi-permeable membrane, to a region of lower water concentration until equilibrium is reached

Answer 19

Osmosis

Question 20

Describes the relative concentration of solutes in a solution compared to another solution.

Answer 20

Tonicity

Question 21

Equal solute concentration

Answer 21

Isotonic

Question 22

Lower solute concentration (water enters the cell)

Answer 22

Hypotonic

Question 23

Higher solute concentration (water leaves the cell)

Answer 23

Hypertonic

Question 24

Refers to the condition where two solutions have the same osmotic pressure across a semipermeable membrane.

Answer 24

Isotonicity

Question 25

In the context of biological systems, it specifically describes a situation where the extracellular fluid and the intracellular fluid have equal solute concentrations, preventing net movement of water into or out of cells.

Answer 25

Isotonicity

Question 26

Cells swell and may burst (lysis) E.g. Drinking excessive water (water intoxication)

Answer 26

Hypotonic

Question 27

Cells maintain normal shape E.g. Properly prepared IV fluids

Answer 27

Isotonic

Question 28

Cells shrink (crenation) E.g. Dehydration, exposure to high-salt environments

Answer 28

Hypertonic

Question 29

It is a general term for a body cell, and all human cells

Answer 29

Somatic cell

Question 30

A cell that develops into a reproductive cell, which is an egg in females and a sperm in males

Answer 30

Germ cell

Question 31

Somatic cells contain ___ copies of each of their chromosomes

Answer 31

Two

Question 32

It is the two copies of a single chromosome found in each somatic cell

Answer 32

Homologous pair of chromosomes

Question 33

The human is a _____

Answer 33

Diploid organism

Question 34

How many homologous pairs of chromosomes in each of the somatic cells

Answer 34

23 homologous pairs of chromosomes

Question 35

The genetic instructions that are used to build and maintain an organism are arranged in an orderly manner in strands of?

Answer 35

DNA

Question 36

are threads of chromatin composed of DNA and associated proteins

Answer 36

Nucleus

Question 37

When a cell is in the process of division, the chromatin condenses into chromosomes, so that the DNA can be safely transported to the?

Answer 37

“Daughter cells”

Question 38

It is composed of DNA and proteins; it is the condensed form of chromatin

Answer 38

Chromosome

Question 39

True or False It is estimated that humans have almost 23,000 genes distributed on 46 chromosomes

Answer 39

**False**: It is estimated that humans have almost **22,000 genes** distributed on 46 chromosomes

Question 40

It is the period of the cell cycle during which the cell is not dividing. The majority of cells are in interphase most of the time

Answer 40

Interphase

Question 41

True or False During interphase, the cell grows and carries out all normal metabolic functions, as well as prepares to divide by replicating its DNA

Answer 41

**True**

Question 42

Each copy of the chromosome is referred to as a _______ and is physically bound to the other copy

Answer 42

Sister chromatid

Question 43

It is the structure that attaches one sister chromatid to another.

Answer 43

Centromere

Question 44

It is the division of genetic material, during which the cell nucleus breaks down and two new, fully functional, nuclei are formed

Answer 44

Mitosis

Question 45

It divides the cytoplasm into two distinctive cells.

Answer 45

Cytokinesis

Question 46

The mitotic phase of the cell typically takes between?

Answer 46

1 and 2 hours

Question 47

What are the two major processes that a cell undergoes?

Answer 47

1. Mitosis 2. Cytokinesis

Question 48

What are the two main phases of the cell cycle?

Answer 48

1. Interphase 2. Mitosis

Question 49

During this process the contents of the nucleus are equitably pulled apart and distributed between its two halves

Answer 49

Mitosis

Question 50

Dividing the cytoplasm and cell body into two new cells.

Answer 50

Cytokinesis

Question 51

What are the four major stages of mitosis?

Answer 51

1. Prophase 2. Metaphase 3. Anaphase 4. Telophase