A&P 1 Unit 4 (Lab) [Cytology]

Question 1

Plasma Membrane

Answer 1

Outer boundary of cell
– Separates the extracellular fluid from the intracellular fluid (cytosol)
• More fluid-like, than rigid, structure
• Creates a selectively permeable barrier
– Allows some, not all, substances across it
• Composed of a phospholipid bilayer
– Type of lipid with hydrophobic and hydrophilic portions
• Contains carbohydrates, proteins, cholesterol
– Carbohydrates are always on the external face
• Attached to membrane proteins and lipids
– Ex. glycoproteins, glycolipids
• Many function as cell “identity” markers for immune system
– Proteins can be integral (embedded) or peripheral (attached to the inner or outer surface)
• Integral membrane proteins function as receptors, channels, transporters, and pumps
– Cholesterol increases the membrane’s strength

Question 2

Cytoplasm

Answer 2

The intracellular region containing the cytosol and the organelles, excluding the nucleus. Consists of: Cytosol, Cytoskeleton, & Organelles

Question 3

Cytosol

Answer 3

Gel-like intracellular fluid. Contains dissolved substances. Bathes the organelles.

Question 4

Nucleus

Answer 4

The largest organelle. Enclosed by the nuclear membrane. Contains most of the cell’s DNA.

Question 5

Cytoskeleton

Answer 5

Protein filaments that function in cell support and movement. (A collection of protein filaments including MICROTUBULES, ACTIN FILAMENTS, & INTERMEDIATE FILAMENTS)

Question 6

Organelles

Answer 6

Intracellular structures and compartments. Each performs specific functions. Many, but not all, are enclosed by their own membrane
(Ex. The nucleus )

Question 7

Microvilli

Answer 7

The plasma membrane of some cells contains microscopic folds, called microvilli. They greatly increase the surface area of the cell. Microvilli are present on cells lining the small intestines, where they increase the surface area for nutrient absorption.

Question 8

Cilia

Answer 8

Cilia are projections (made of particular cytoskeletal filaments) that move substances across the cell surface. (Examples of ciliated cells: Cells lining the trachea [windpipe] & Cells lining the uterine tube [fallopian tube])

Question 9

Flagellum

Answer 9

Cell projection (contains particular cytoskeletal filaments) that functions to move the cell. (Only flagellated cell in humans is sperm)

Question 10

Diffusion

Answer 10

Movement of a substance from an area of higher concentration to an area of lower concentration.

Question 11

Factors that increase the rate of diffusion

Answer 11

1) Rise in temperature
2) Smaller molecule size
3) Higher concentration gradient
4) Shorter distance

Question 12

Factors the decrease the rate of diffusion

Answer 12

1) Drop in temperature
2) Bigger molecule size
3) Lower concentration gradient
4) Longer distance

Question 13

Osmosis

Answer 13

Movement of the solvent from a solution with lower solute concentration to a solution with a higher solute concentration through a selectively permeable membrane.

Question 14

Tonicity

Answer 14

The concentration of a solution outside of a cell compared to with the concentration of the cytosol.

Question 15

3 types of Tonicity

Answer 15

1) Hypotonic
2) Isotonic
3) Hypertonic

Question 16

Hypotonic

Answer 16

A hypotonic solution has a lower solute concentration than the cytosol. A cell placed in a hypotonic solution will gain water by osmosis and may swell and burst. (CELLS SWELL)

Question 17

Isotonic

Answer 17

An isotonic solution has the same solute concentration as the cytosol. There is no concentration gradient to drive osmosis, so there is no net movement of water into or out of a cell in an isotonic solution. (CELLS STAY THE SAME)

Question 18

Hypertonic

Answer 18

A hypertonic solution has a higher solute concentration than the cytosol. A cell in a hypertonic environment will lose water by osmosis and shrivel or CRENATE, because water will be drawn toward the more concentrated solution. (CELLS SHRINK)

Question 19

8 types of Organelles

Answer 19

1) Ribosomes
2) Peroxisomes
3) Mitochondria
4) Endoplasmic reticulum
5) Golgi apparatus
6) Lysosomes
7) Centrioles
8) Nucleus

Question 20

Ribosomes

Answer 20

The small, granular ribosomes are not surrounded by a membrane and are composed of two subunits. Some ribosomes float freely in the cytosol, whereas others are bound to the membrane of another organelle or the nucleus. Ribosomes are the sites of protein synthesis in the cell.

Question 21

Peroxisomes

Answer 21

The small, vesicular organelles known as peroxisomes contain enzymes that detoxify chemicals produced by cellular reactions, metabolize fatty acids, and synthesize certain phospholipids.

Question 22

Mitochondria

Answer 22

The bean-shaped mitochondria are double-membrane-bounded organelles that produce the bulk of the cell’s ATP (energy).

Question 23

Endoplasmic reticulum

Answer 23

The series of membrane-enclosed sacs known as the endoplasmic reticulum may be of two types: ROUGH ENDOPLASMIC RETICULUM, or RER, which has ribosomes on its surface, and SMOOTH ENDOPLASMIC RETICULUM, or SER, which lack ribosomes. RER functions in protein synthesis and modifies proteins that the ribosomes have made. SER has multiple functions, including lipid synthesis and detoxification reactions.

Question 24

Golgi apparatus

Answer 24

The Golgi apparatus is a stack of flattened sacs near the RER. Its membrane-enclosed sacs receive vesicles from the RER and other places in the cell and process, modify, and sort the products with in the vesicles.

Question 25

Lysosomes

Answer 25

Lysosomes are sacs filled with digestive enzymes that digest particles brought into the cell, old and worn-out organelles, and even the cell itself.

Question 26

Centrioles

Answer 26

Centrioles are paired organelles composed primarily of microtubules that are located in the central area of the cell called the CENTROSOME. They appear to be microtubule organizing centers and are important in facilitating the assembly and disassembly of microtubules.

Question 27

Nucleus

Answer 27

Specialized organelle. The nucleus is the cell’s biosynthetic center, which directs the synthesis of all of the body’s proteins, as well as certain nucleic acids. The nucleus is surrounded by a double membrane called the NUCLEAR ENVELOPE, which contain holes called NUCLEAR PORES. Within the nucleus we find CHROMATIN, a ball-like mass of tightly coiled DNA and proteins; RNA; and a dark-staining region called the NUCLEOLUS. The nucleolus contains a type of RNA called RIBOSOMAL RNA and is the “birthplace” of ribosomes.

Question 28

Composition of the Plasma Membrane

Answer 28

It is composed of a phospholipid bilayer with multiple components interspersed throughout, including INTEGRAL PROTEINS, PERIPHERAL PROTEINS, CHOLESTEROL, GLYCOPROTEINS, & GLYCOLIPIDS. It is a dynamic, fluid structure that acts as a selectively permeable barrier. In parts of the body where rapid absorption is necessary, the plasma membrane is folded into projections called MICROVILLI, which increase its surface area.

Question 29

Phospholipid

Answer 29

Head is polar (Hydrophilic); 2 “tails” are non-polar (Hydrophobic)

Question 30

What makes cholesterol?

Answer 30

The liver