Chapter 3

Question 1

What is a cell?

Answer 1

basic unit of structure and function in the body

Question 2

What is the function of the plasma membrane?

Answer 2

• surrounds and gives cell form
• selectively permeable
• formed by phospholipid bilayer

Question 3

What is the function of proteins in the plasma membrane?

Answer 3

• provide structural support
• serve as transporters, enzymes, receptors and identity markers

Question 4

What is the function of carbohydrates in the plasma membrane?

Answer 4

glycoproteins and glycolipids
- impact negative charge to surface
- can serve as cell surface markers (antigens)

Question 5

What is bulk transport?

Answer 5

how cells move large molecules and particles across the plasma membrane
- phagocytosis
- endocytosis
- pinocytosis (nonspecific)
- exocytosis to export products

Question 6

What are cilia for?

Answer 6

movement

Question 7

What are flagella for?

Answer 7

movement

Question 8

What are microvilli for?

Answer 8

absorption and membrane transport
- increases surface area

Question 9

Where are cilia located? What does it look like?

Answer 9

surface of epithelial cells
- hair-like structures that beat in unison
- contains microtubules

Question 10

What is the cytoplasm?

Answer 10

jellylike matrix
- cytosol + organelles

Question 11

What is the cytoskeleton?

Answer 11

microfilaments and microtubules in the cytoplasm
- gives cell its shape and structure

Question 12

What are lysosomes and their function?

Answer 12

vesicle-like organelles containing digestive enzymes
- recycles cell components
- programmed cell death

Question 13

What is the function of peroxisomes?

Answer 13

detoxification in liver

Question 14

What is the function of mitochondrias?

Answer 14

energy producers

Question 15

What are the functions of ribosomes?

Answer 15

protein factories
- 2 rRNA subunits

Question 16

What is the function of the endoplasmic reticulum?

Answer 16

• synthesis or degradation of molecules
• rough: protein synthesis
• smooth: steroid synthesis and inactivation

Question 17

What is the function of the golgi complex?

Answer 17

vesicles enter from ER, contents are modified, and then they leaves
- lysosomes and secretory vesicles are formed in the golgi

Question 18

What is the function of the nucleus?

Answer 18

contains cell’s DNA
- enclosed by nuclear envelope

Question 19

What do nuclear pore complexes do?

Answer 19

fuse inner and outer membranes together
- small molecules can diffuse through pores
- proteins, RNA are actively transported

Question 20

What does genome mean?

Answer 20

all genes in an individual or of a species

Question 21

What is proteome?

Answer 21

all proteins produced by a genome

Question 22

What is the central dogma of biology?

Answer 22

DNA -> RNA -> Protein

Question 23

What is transcription?

Answer 23

DNA -> RNA
- occurs in the nucleus and never in the cytoplasm

Question 24

What is a gene?

Answer 24

sequence of nucleotides that is chemical set of instructions for making a specific protein

Question 25

What is translation?

Answer 25

RNA -> protein - occurs in cytoplasm and never in the nucleoplasm - linear sequence of mRNA determines linear sequence of nucleotides linear sequence of amino acids make up a protein

Question 26

What are nucleoli?

Answer 26

dark areas in a nucleus containing genes actively making rRNA

Question 27

What is chromatin?

Answer 27

DNA and its associated proteins (histones)

Question 28

What are histones?

Answer 28

positively charged and form spools around negatively charged DNA strands - histone + DNA = nucleosome

Question 29

What is the function of RNA polymerase?

Answer 29

binds to a "start" sequence on DNA and unzips strands

Question 30

What are promotor regions for?

Answer 30

regulates levels of transcription

Question 31

What do transcription factors do?

Answer 31

bind to promoter sequence to initiate transcription

Question 32

What base pairs are complementary to each other?

Answer 32

G pairs with C A pairs with U

Question 33

What 4 types of RNA does transcription produce? What are their functions?

Answer 33

- pre-mRNA: changes in nucleus to form mRNA - mRNA: contains code for synthesis of a protein - tRNA: decodes info contained in mRNA - rRNA: forms part of ribosomes

Question 34

How does pre-mRNA work?

Answer 34

introns: non-coding regions Exons: coding regions - introns are removed and ends of exons spliced together to produce mRNA

Question 35

How does DNA replication work?

Answer 35

1) Helicase breaks hydrogen bonds to produce 2 free strands of DNA. 2) DNA polymerase binds to each strand and makes new complementary copy of old strand 3) Each copy is composed of 1 new strand and 1 old strand (semiconservative replication)

Question 36

What phase do most cells exist in?

Answer 36

interphase

Question 37

What is the cell cycle?

Answer 37

G1 - cell performs normal physiological roles S - DNA is replicated in preparation for division G2 - chromatin condenses prior to division

Question 38

What is mitosis?

Answer 38

cell division - chromosomes are condensed and duplicated (2 duplicate strands [chromatids] + connection [centromere])

Question 39

What are the stages of mitosis?

Answer 39

Prophase: chromosomes are visible Metaphase: chromosomes line up single file along equator by spindle fibers Anaphase: centromeres split towards opposite poles Telophase: cytoplasm is divided producing 2 daughter cells