Ch 3. The cell

Question 1

cell/plasma membrane

Answer 1

bilayer of:
1. phospholipids- diglycerides and form a bilayer. Permits non-polar substances to pass through but blocks polar or charged substances from passing through.
2. cholesterol- stabilizes the cell membrane
3. Carrier enzyme or carrier protein- it’s a protein that is part of the cell membrane and helps transports materials across the membrane.
Important to nerve + muscle cells bc of electrical impulses

Question 2

Membrane proteins
(Channel proteins , Receptor sites, Antigens)

Answer 2

1. Channel proteins or pores- permit the passage of materials into and out of the cell
2. Receptor sites- a type of protein that recognizes certain hormones or chemicals needed by the cell
3. Antigens- proteins with an oligosaccharide identify “self”. Involved in tissue typing used by white blood cells to distinguish pathogens

Question 3

nucleus + nucleolus

Answer 3

the membrane-bound organelle which contains our DNA and controls all cellular activities.
All your body’s cells have a nucleus except red blood cells (RBC’s).
Nucleolus- a smaller sphere inside the nucleus where ribosomes are made.

Question 4

chromosomes

Answer 4

rod shaped structures containing super condensed DNA & proteins. Appear when the cell is ready to divide.
Humans have 23 pairs or 46 total.

Question 5

chromatin

Answer 5

non-condensed DNA found in the nucleus. Our DNA usually takes this form.

Question 6

Gene

Answer 6

is the genetic code for a protein. One gene-one protein.

Question 7

Cytosol

Answer 7

-is the watery portion of the cytoplasm. It contains many dissolved minerals, gases, proteins, etc.

Question 8

Cytoskeleton

Answer 8

protein microfilaments which gives the cell shape and support

Question 9

ribosomes

Answer 9

make proteins and are found on the rough ER or free floating in the cytosol

Question 10

Golgi Apparatis

Answer 10

series of flattened sacs which process materials for secretion out of the cell.
Carbohydrates are synthesixed withing this organelle

Question 11

mitochondria

Answer 11

site of ATP synthesis. Inner folds are called cristae. Contain their own DNA inherited maternally.

Question 12

lysosome

Answer 12

contain digestive enzymes

Question 13

Proteasomes

Answer 13

barrel-shaped organelles that contain protein digesting enzymes
important for cell division and embryonic development

Question 14

Centrioles

Answer 14

rod shaped structures which organize the spindle fibers during cell division.

Question 15

cillia

Answer 15

short hair-like projections that work in unison to MOVE OBJECTS across the free surface. Found in the respiratory tract & fallopian tubes.

Question 16

FLAGELLA

Answer 16

longer hair-like projection used for movement. Ex: sperm

Question 17

Mircovilli

Answer 17

small folds found on the surface of some cells of the digestive tract which increase surface area of the cell for absorption of nutrients.

Question 18

Endoplasmic reticulum

Answer 18

passageway for transport of materials within the cell
Rough ER- has ribosomes on its surface
synthesizes proteins
Smooth ER- synthesize lipids and detoxify chemicals

Question 19

PASSIVE CELLULAR TRANSPORT

Answer 19

1. Diffusion- the movement of molecules from an area of high concentration to an area of lower concentration.
Ex: oxygen & carbon dioxide
2. Osmosis- diffusion of water across a membrane. Water moves from high water conc. to lower water conc. occurs in kidneys reabsorb large amounts of water to prevent its lost in urine/small intestine absorb water from digest food
3. Facilitated diffusion- a process where a substance crosses the cell membrane using a protein (enzyme) carrier. Ex: glucose

Question 20

osmosis

Answer 20

1. Isotonic- equal parts of solutes
2. Hypotonic solution- having a lower concentration of dissolved particles. Will cause a cell to swell. Ex: distilled water
3. Hypertonic solution- having a higher concentration of dissolved particles. Will cause a cell to shrink. Ex: ocean water.

Question 21

ACTIVE CELLULAR TRANSPORT

Answer 21

-Requires ATP
b/c you’re moving from moving against the concentration gradient
1. Sodium-Potassium Pump (Na/K Pump)-
2. Filtration-
3. Endocytosis-
4. Exocytosis-

Question 22

Sodium-Potassium Pump (Na/K Pump)-

Answer 22

a very important ion pump in nerve and muscle cells.
Moves Na & K against their conc gradients. 3 Na out:2 K in

Question 23

Filtration-

Answer 23

requires the use of mechanical pressure.

Question 24

Endocytosis

Answer 24

a process by which materials enter the cell by vesicles.
2 Types:
Phagocytosis- engulfing another cell or large particle. Ex: white blood cell engulfing a bacteria.
Pinocytosis- engulfing fluids or smaller particles. Ex: kidneys reabsorb proteins so not loss in urine

Question 25

Exocytosis-

Answer 25

the process by which materials are secreted by vesicles.

Question 26

codon

Answer 26

sequence of three bases (triplet code) in mRNA which codes for a particular amino acid.

Question 27

DNA

Answer 27

a double strand of nucleotides in the shape of a double helix. base pairing: Adenine-Thymine Guanine- Cytosine Uracil- a nucleotide in RNA which takes the place of Thymine. A-U base pairing.

Question 28

mRNA

Answer 28

messenger RNA takes the genetic code from DNA in the nucleus out to the ribosomes for translation. mRNA is a series of codons

Question 29

Transcription

Answer 29

copying the DNA to mRNA. “DNA to RNA”

Question 30

tRNA

Answer 30

transfer RNA is found in the cytoplasm and contains the anticodons. It also has a specific amino acid attached.

Question 31

Translation

Answer 31

is the process in which ribosomes in the cytoplasm or endoplasmic reticulum synthesize proteins. “DNA to Protein”

Question 32

mitosis

Answer 32

cell reproduction where a cell divides and produces two identical daughter cells. Occurs in all cells except reproductive cells. Necessary for growth and repair of tissues.

Question 33

meiosis (and the 2 types)

Answer 33

cell division where a reproductive cell divides and reduces the chromosome by a half to produce haploid gametes. Haploid n=23...diploid 2n=46 Oogenesis- meiosis in the ovaries produce egg cell. Spermatogenesis- meiosis in the testes produce sperm cells.

Question 34

aging of cells

Answer 34

**telomeres**- the ends of chromosomes. after each cell division, a small portion of the telomeres is lost resulting in a loss of the chromosome and/or DNA. **Chaperones**- proteins responsible for maintaining cellular activities. They work less effectively resulting in a build-up of damaged proteins in the cell. **The accumulation of damaged proteins interferes with proper cellular function.**