Chapter 3 - Cellular Level of Organization

Question 1

2 Types of cells

Answer 1

somatic and sex

Question 2

Cell membrane

Answer 2

physical barrier, and provides structural support

Question 3

Membrane Structure

Answer 3

a phospholipid bilayer that keeps the composition inside and outside the cell different. A very selective hydrophilic heads and hydrophobic tails.

Question 4

Membrane Proteins

Answer 4

Anchor one cell to another, recognize neighboring cells, enzymes, hormone receptors, carrier proteins, channels, and electron transferers.

Question 5

Peripheral proteins

Answer 5

attached to the inner or outer surface of the membrane

Question 6

Integral proteins

Answer 6

part of the membrane structure

Question 7

Membrane Permability

Answer 7

passive - movement without energy; active - movement what requires energy, usually ATP.

Question 8

Diffusion

Answer 8

Passive; involved distance, size, temperature. Movement direction depends on concentration

Question 9

Osmosis

Answer 9

Diffusion of water that goes from an area of higher concentration to a lower concentration. It involves pressure called osmotic pressure.

Question 10

Isotonic

Answer 10

The concentration in an d out of the cell is the same

Question 11

Hypotonic

Answer 11

Higher concentration outside the cell, water toxification.

Question 12

Hypertonic

Answer 12

Higher concentration inside the cell, dehydration

Question 13

Filtration

Answer 13

movement across a membrane, that depends on pressure and size of pores in that membrane

Question 14

Facilitated Transport

Answer 14

Carrier proteins transport solutes, channel proteins

Question 15

Active Transport

Answer 15

Uses energy, important in transporting ions, ex: the sodium/potassium pump.

Question 16

Endocytosis

Answer 16

Substances are imported into the cell.

Question 17

Pinocytosis

Answer 17

The cell “gulps” a drop of extracellular fluid with solutes into vesicles.

Question 18

Receptor Mediated Endocytosis

Answer 18

substances bind to receptor proteins enabling the cell to ingest specific substances in protein coated vesicles.

Question 19

Phagocytosis

Answer 19

the cell engulfs a large particle by forming projectile pseudopods around it and enclosing it in a membrane

Question 20

Exocytosis

Answer 20

Substances are exported from the cell

Question 21

Cytoplasm

Answer 21

Material found in the cell but outside the nucleus, high in K+, low in Na+, water, high in proteins and lipids, low in carbohydrates.

Question 22

Microfilaments

Answer 22

Protein strands mostly actin,they are involved in cell motility. Found in muscle cells and mobile cells

Question 23

Intermediate filaments

Answer 23

provide support to help maintain the shape of a cell. tough insoluble protein fibers constructed like woven ropes

Question 24

Thick filaments

Answer 24

Bundles of myacin protein subunits, found only in muscle cells

Question 25

Microtubules

Answer 25

found in all cells, has the protein tubulin forming the primary components of the cytoskeleton. Gives cell strength, helps anchor cells and major organelles, and is involved in cell division.

Question 26

Microvilli

Answer 26

Projections of the cell membrane that increase the surface area

Question 27

Centrioles

Answer 27

Barrel shaped; composed of microtubules found in 9 groups of 3. Found in cells that divide forming the spindle apparatus

Question 28

Centrosome

Answer 28

cytoplasm surrounding the centrioles

Question 29

Cilia

Answer 29

9 pairs of microtubules forming very short projections whose sole purpose is to move matrial over the surface of the cel.

Question 30

Flagella

Answer 30

Long projection made of microtubules that moves the cell, ex: sperm

Question 31

Ribosomes

Answer 31

Assemble amino acids into proteins. Free - floating through the cytoplasm. Fixed - attached to the rough edoplasmic reticulum.

Question 32

Mitochondria

Answer 32

Double membranes organelle that produces energy (ATP) from carbohydrates, especially glucose.

Question 33

Endoplasmic Reticulum

Answer 33

Intracellular membranes connected to the nuclear envelope.

Question 34

Smooth ER

Answer 34

Synthesize lipids, steroid hormones, glycerides, and glycogen. Detoxification of drugs and toxins. Storage of calcium and large molecules.

Question 35

Rough ER

Answer 35

Outer surface has ribosomes, where proteins are synthesized then transferred to the golgi apparatus and into the transport vesicles.

Question 36

Golgi Apparatus

Answer 36

Flattened discs called saccules. Most stacks lie near the nucleus and the ER because of the necessary communication. Synthesize and package proteins and secretions for exocytosis and for the cytosol.

Question 37

Lysosomes

Answer 37

Vesicles from the golgi apparatus containing enzymes. they break down food, debris, and bacteria. they also break down bone to release calcium.

Question 38

Peroxisomes

Answer 38

Smaller than lysosomes, carry different enzymes and derive from the ER. They're most abundant in liver cells because they either remove or neutralize toxins. They oxidize free radicals.

Question 39

Nucleus

Answer 39

Control center of the cell

Question 40

Nuclear Envelope

Answer 40

A phospholipid double membrane separated by a perinuclear space. Made up of nucleoplasm and nuclear matrix

Question 41

DNA

Answer 41

contains hereditary information; found in the chromosome. Wrapped around proteins called histones, forming a complex known as a nucleosome. When DNA is not dividing, it is in thread-like strands called chromatin

Question 42

Nucleoli

Answer 42

Nuclear organelles that synthesize ribosomal RNA (rRNA)

Question 43

Genetic Code

Answer 43

The triplet code; consists of 3 bases, each gene contains all triples needed to produce a certain protein

Question 44

Transcripltion

Answer 44

transfer of information from a DNA base sequence to the complementary base sequence of an mRNA molecule. Happens in the Nucleus

Question 45

Initiation

Answer 45

DNA unwinds and content segment is exposed

Question 46

Elongation

Answer 46

RNA polymerase tracels along DNA strand, moving from triplet to triplet. Making a mRNA strand.

Question 47

Termination

Answer 47

At a stop signal, transcription ends, mRNA is edited to get rid of introns and enters the cytoplasm

Question 48

Translation

Answer 48

The language of nuclei acids is translated into the language of proteins. In the cytoplasm

Question 49

Translation Sequence

Answer 49

1. mRNA bings to the light ribosomal unit and scans for the strat codon (AUG) 2. Anticodon is brought by the tRNA (UAC) and the heavy ribosomal unit attaches to the light leaving the mRNA to slip throught the gap in the two. 3. Enzyme breaks the link between the tRNA and its animo acid in the P-site. 4. The amino acid is bonded to another one the next one by a peptide bond. 5. Continues until the mRNA reaches a stop codon (UGA, UAA, UAG)

Question 50

Polyribosomes

Answer 50

a series of ribosomes attached to the same mRNA strand producing many proteins at the same time.

Question 51

Meiosis

Answer 51

Cell divisiton producint gametes or sex cells

Question 52

Mitosis

Answer 52

Cell division producing clones. Essential for growth and tissue repair. Continuous in some tissue, like the skin, intestinal tissue. None in the nerve tissue, skeltal muscle, or cardiac muscle.

Question 53

Interphase

Answer 53

G0) The cell is not dividing, not in mitosis, normal cell function. G1) Manufacturing material that is needed to divide, centriole replication begins. S) chromosomes duplicate G2) More preparation for division, protein synthesis, centriole replication is completed.

Question 54

Prophase

Answer 54

Early) Two copies of each chromosome with a centromere in the middle surrounded by a protein complex called kinetochore. Nuclear envelope fragments and centrioles move to opposite poles with spindle fibers in between. Late) Nuclear envelope disappears

Question 55

Metaphase

Answer 55

Chromatids are moving towards the middle

Question 56

Anaphase

Answer 56

Centromeres of the chormosomes split. Each chromatid becomes a chromosome. Cytokinesis begins very late in this phase. Shortest phase.

Question 57

Telophase

Answer 57

Begins when the choromosome movement stops. They uncoil to form chromatin. New nuclear envelope forms, nucleoli reappear, spindle disappears. Cytokineses with full division of cytoplasm is completed

Question 58

Differentiation

Answer 58

The process of forming specialized cells and tissues

Question 59

Tight Junctions

Answer 59

Adjacent integral proteins that fuze the cells. Prevent liquids and most molecules from moving between the cells

Question 60

Desmososmes

Answer 60

Transmembrane proteins that rivot the cells together at the plasma membranes cementing them together, making them very strong. Found in skin layers and cardiac muscle.

Question 61

Gap Junctions

Answer 61

Channel proteins forming pores, connexons, allowing small molecules/ions to move the cell to cell. Important in cardiac muscle and smooth muscle because it moves the action potential.