Cytology

Question 1

Cytology

Answer 1

the study of cells

Question 2

Cells

Answer 2

the structural and functional units of all living things

Question 3

generalized cell

Answer 3

diagram of cells that we often see - no cell appear just like it but it’s a useful way to look at the cell components

Question 4

Plasma membrane

Answer 4

the outer shell of a cell

Question 5

two key functions of the plasma membrane

Answer 5

1. separates the cell from its environment
2. allows selective passage of materials in or out of the cell

Question 6

plasma membrane structure

Answer 6

-phospholipid bi-layer with proteins embedded in it

• some proteins act as channels or gates through which substances can move in or out of the cell

-other proteins act as “receptors” that bind to specific molecules such as hormones or serve as “markers” to identify the cell as “self”

Question 7

membrane transport may be either

Answer 7

active or passive

Question 8

Active transport

Answer 8

requires energy

moves substances against their concentration gradient - from areas of lesser to greater concentration

Example: sodium potassium pump

Question 9

passive transport

Answer 9

involves no energy expenditure

Question 10

Diffusion

Answer 10

when a substance moves from greater concentration to lesser concentration

a passive process and may occur directly through the plasma membrane or through protein channels

Question 11

Osmosis

Answer 11

diffusion of water - water moves from areas of greater concentration to lesser

passive mechanism that moves water in or out of cells, from one part of our body to another

Question 12

Vesicles

Answer 12

small sacs formed by pinching off a piece of an existing membrane, enclosing some substances within the sac

some are used to store substances, some may be involved in transport across membranes

Question 13

Vesicular transport

Answer 13

moves things in or out of cells by using vesicles

Question 14

endocytosis (type of vesicular transport)

Answer 14

vesicles are formed to “envelop” some extracellular substance to bring it into the cell

Question 15

exocytosis (type of vesicular transport)

Answer 15

vesicles inside the cell “fuse” with the existing plasma membrane of the cell and releases substances to the extracellular fluid

Question 16

cytoplasm

Answer 16

refers to all of the substances inside of the plasma, with the exception of the nucleus

consists of two major parts - cytosol and organelles

Question 17

cytosol

Answer 17

the fluid portion of the cell

usually makes up 55% of the volume of a typical cell

primarily water with various dissolved substances like glucose, amino acids, ATP, and wastes

Question 18

Cytoskeleton

Answer 18

a network of protein filaments that extends through the cytosol

consists of microfilaments, intermediate filaments, and microtubules

Question 19

role of cytoskeleton

Answer 19

provides support, shape, and factors into movement of cells

Question 20

Nucleus

Answer 20

often spherical or oval-shaped
often the largest structure in the cell

most cells have a nucleus - RBC’s do NOT

Skeletal muscles have multiple

has nuclear envelope that separates the nucleus from the cytoplasm of the cell

Question 21

Nucleoli

Answer 21

within the nucleus

role is producing ribosomes

consists of protein, DNA, and RNA.

Genetic material

contains blueprint for cellular activity

Question 22

major components of cytoplasm

Answer 22

cytosol and organelles

Question 23

organelles include

Answer 23

mitochondria
lysosomes
centrosomes
cilia and flagella
ribosomes
endoplasmic reticulum
Golgi complex

Question 24

Mitochondria

Answer 24

organelle that produce ATP, used to supply energy for cellular activity

cells that are very active (such as muscle cells) tend to have numerous mitochondria

Question 25

Lysosomes

Answer 25

vesicles filled with powerful digestive enzymes these enzymes may break down worn-out cell structures, entire cells, or extracellular structures Peroxisomes and proteasome are similar to lysosomes but use different types of enzymes

Question 26

Centrosome

Answer 26

located near the nucleus and contains a pair of structures known as centrioles these organelles (centrosomes and centrioles) have important roles in cell division

Question 27

Cilia

Answer 27

numerous, short hair-like projections on the surface of some cells tend to "wave" together to move fluid along the surface of a cell many cells of the respiratory tract have cilia to move mucus and inhaled particulate matter away from the lungs

Question 28

Flagella

Answer 28

single projections similar to cilia but much longer they move the ENTIRE CELL, such as a sperm cell

Question 29

ribosomes

Answer 29

site of protein synthesis the subunits of ribosomes are synthesized in the nucleoli within the nucleus. these subunits are then assembled in the cytoplasm some ribosomes are "free" (unattached to other structures), some are found within mitochondria, and some are attached to other structures such as the endoplasmic reticulum

Question 30

endoplasmic reticulum

Answer 30

a network of membranes that extent from the nuclear envelope into the cytoplasm

Question 31

two types of ER

Answer 31

1. rough - has ribosomes attached to the outer surface and serves as a site to process and sort proteins synthesized in the ribosomes 2. smooth - does not have ribosomes and synthesizes other non-protein substances such as lipids

Question 32

Golgi complex

Answer 32

consists of numerous flattened membranous sacs sorts and packages substances such as proteins, often into vesicles

Question 33

protein synthesis

Answer 33

two key processes 1. transcription 2. translation

Question 34

Transcription

Answer 34

where info stored in the DNA within the nucleus is copied (transcribed) to produce a specific molecule of RNA

Question 35

3 types of RNA created by transcription

Answer 35

1. Messenger RNA - directs synthesis of a protein 2. Ribosomal RNA - joins with other proteins to make ribosomes 3. Transfer RNA - holds amino acids in place as they pieced together into a protein

Question 36

Translation

Answer 36

where the transcribed molecule of RNA attaches to a ribosome and the information contained is converted (translated) into a sequence of amino acids to form new protein

Question 37

Cell division

Answer 37

most cells reproduce themselves by way of cell division

Question 38

Mitosis

Answer 38

the process by which all cells except gametes (sex cells) reproduce one cell divides to produce two identical cells, each with a full compliment of genetic material

Question 39

Meiosis

Answer 39

gametes (sperm and egg cells) undergo a different type of cell division called meiosis, where the genetic material of a cell is halved