Organelles

Question 1

Ribosomes

Answer 1

site of protein synthesis
Consists of two subunits: each w/ ribosomal RNA and bound to protein molecules

Question 2

Nucleus

Answer 2

Usually the largest organelle,
Site of DNA replication,
Contains most of DNA
Site where gene transcription is turned on or off, Assembly of ribosomes begins in nucleolus

Question 3

DNA combines w/ proteins to form _____ in long, thin strands call _____

Answer 3

Chromatin; Chromosomes

Question 4

The nucleus is surrounded by the _____, a double membrane

Answer 4

Nuclear envelop

Question 5

____ in the envelope control movement of molecules across the envelope

Answer 5

Nuclear pores

Question 6

The outer membrane is continuous with the ____

Answer 6

Endoplasmic reticulum

Question 7

Endomembrane system

Answer 7

Interconnected system of membrane-enclosed compartments

Question 8

What does the endomembrane system include

Answer 8

Nucleus, endoplasmic reticulum, golgi apparatus, and vesicles

Question 9

Vesicles

Answer 9

Shuttles substances between various compartments

Question 10

Endoplasmic reticulum

Answer 10

Network of membranes in the cytoplasm; large surface area

Question 11

Rough endoplasmic reticulum

Answer 11

Ribosomes are attached; newly made proteins enter the RER lumen and are modified, folded, and transported to other regions in vesicles that pinch off from the RER lumen

Question 12

Smooth endoplasmic reticulum

Answer 12

No ribosomes; chemically modifies small molecules such as drugs and pesticides

Question 13

What is the function of the SER

Answer 13

Site of glycogen degradation in animal cells; synthesis of lipids and steroids; and stores calcium ions

Question 14

Golgi apparatus

Answer 14

Flattened sacs (cisternae) and small vesicles; receives proteins from the RER; modifies, concentrates, packages, and sorts proteins
In plant cells, polysaccharides for cell walls are synthesized here

Question 15

Mitochondria

Answer 15

Energy in fuel molecules such as glucose is transformed to the bonds of energy-rich ATP; two membranes; can reproduce and divide independently of the central nucleus

Question 16

Inner membrane folds inward to form _____ and creates large surface area for the embedded proteins involved in cellular respiration

Answer 16

Cristae

Question 17

Mitochondrial matrix contains ____ and _____ to make proteins needed for cellular respiration

Answer 17

DNA; ribosomes

Question 18

Plastids

Answer 18

Only in plants and some protists

Question 19

Chloroplasts

Answer 19

Site of photosynthesis; have a double membrane and can divide independently of the nucleus

Question 20

The chloroplasts inner membrane forms _____ which contains chlorophyll and other pigments that harvest light energy

Answer 20

Thylakoids

Question 21

Chromoplasts

Answer 21

Contain red, orange, and yellow pigmentss which give color to flowers

Question 22

Leucoplasts

Answer 22

Store starches and fats

Question 23

Peroxisomes

Answer 23

Collect and break down toxic byproducts of metabolism such as H2O2, using specialized enzymes

Question 24

Gyloxysomes

Answer 24

Only in plants; lipids are converted to carbohydrates for growth

Question 25

Vacuoles

Answer 25

Provide structure for plant cells- water enters the vacuole by osmosis, creating turgor pressure

Question 26

What do vacuoles store

Answer 26

Anthocyanins (pink and blue pigments) in flowers and fruits; the colors attract pollinators

Question 27

Food molecules enter the cell by _____

Answer 27

Phagocytosis

Question 28

Lysosomes

Answer 28

Contain digestive enzymes that hydrolyze macromolecules into monomers

Question 29

Primary lysosome

Answer 29

Originate from golgi apparatus

Question 30

Phagosomes fuse with primary lysosomes to form ___. Enzymes hydrolyze the food molecules

Answer 30

Secondary lysosomes

Question 31

Wastes are ejected by _____

Answer 31

Exocytosis

Question 32

Cytoskeleton

Answer 32

Supports and maintains cell shape, holds organelles in position, moves organelles, involved in cytoplasmic streaming, interacts with extracellular structures to hold cell in place, composed of three types of filaments

Question 33

Pili

Answer 33

hairlike structures projecting from the cell surface. They help bacteria adhere to other cells

Question 34

Some prokaryotes swim using _____, made of the protein flagellin

Answer 34

Flagella

Question 35

Why is surface area-volume ratio important

Answer 35

As cell volume increases, chemical activity increases, alone with the need for resources and waste removal. Because resources and waste come in and out through the membrane, surface area becomes limited

Question 36

Cell membrane

Answer 36

Selectively permeable barrier, allows cells to maintain a constant internal environment, important in communication and receiving signals

Question 37

Microfilaments

Answer 37

Help a cell or parts of a cell move, determine cell shape, made from actin, have a plus and minus end, can change length rapidly by adding actin to plus end or losing it from minus end

Question 38

Actin polymerizes to from long ______

Answer 38

Helical chains (reversible)

Question 39

______ are associated with localized changes in cell shape including cytoplasmic streaming and amoeboid movement

Answer 39

Actin filaments

Question 40

Micofilaments are also involved in the formation of

Answer 40

Pseudopodia

Question 41

Intermediate filaments

Answer 41

Tough, ropelike structures; anchors cells in place

Question 42

Microtubules

Answer 42

Long, hollow cylinders; form a rigid internal skeleton; act as a framework for motor proteins

Question 43

What are microtubules made from

Answer 43

Dimers of the protein tubulin; can change length rapidly by adding or losing dimers at plus and minus ends

Question 44

Cell movement

Answer 44

Cilia and eukaryotic flagella are made of microtubules in 9+2 array

Question 45

______ serve as tracks for motor proteins, which move vesicles or organelles from one part of the cell to another

Answer 45

Microtubules

Question 46

_____ binds to a vesicle and "walks" it along by changing shape

Answer 46

Kinesin

Question 47

Kinesins move materials towards the ____ end and dyneins move materials towards the ____ end

Answer 47

Plus, minus