Chapter 7 Homework

The structure of a chloroplast is closely tied to its function as the site of photosynthesis. Some of the following statements are true for chloroplasts; others are true for mitochondria. Which statements are true for chloroplasts? Select the three that apply.

1) They are the sites of reactions that convert solar energy into chemical energy. 2) They contain the green pigment chlorophyll. 3) They have membranous sacs called thylakoids that are surrounded by a fluid called stroma.

Which of these structures stores, modifies, and packages products?

A

The Golgi apparatus has a polarity, or sidedness, to its structure and function. Which of the following statements correctly describes this polarity?

All of the listed responses correctly describe polarity characteristics of the Golgi function.

_____ is/are identical in structure to centrioles.

Basal bodies

Choose the letter that indicates the organelle that contains most of a cell's DNA.

C

The structure that regulates the passage of material into and out of this bacterial cell is indicated by the letter _____.

C

The DNA-containing region of this bacterial cell is indicated by the letter _____.

D

Why is the smooth endoplasmic reticulum unable to synthesize proteins?

No ribosomes are attached to its surface.

_____ are the sites of protein synthesis.

Ribosomes

Which of the following correctly pairs the organelle with the function of the organelle in prokaryotes?

The photosynthetic membranes have a large surface area to hold pigments and enzymes to increase food production.

What are three attributes of mitochondria and chloroplasts that suggest they were once free-living bacteria?

They have their own small, often circular chromosomes; they produce their own ribosomes; and they replicate independently of cellular division.

Which of the following is NOT found in a prokaryote?

a mitochondrion

A prokaryotic cell is distinct from a eukaryotic cell because a prokaryotic cell lacks _____.

a nucleus

All of the following are part of a prokaryotic cell EXCEPT _____.

an endoplasmic reticulum

Lysosomes are considered to be part of the endomembrane system because they ________.

are formed from products synthesized by the endoplasmic reticulum and processed by the Golgi

What name is given to the rigid structure, found outside the plasma membrane, that surrounds and supports the bacterial cell?

cell wall

The _____ is composed of DNA and protein.

chromatin

In a plant cell, DNA may be found _____.

in the nucleus, mitochondria, and chloroplasts

Endocytosis moves materials _____ a cell via _____.

into ... membranous vesicles

Which of the following contains hydrolytic enzymes?

lysosome

Which organelle plays a role in intracellular digestion?

lysosome

Which of these are hollow rods that shape and support the cell?

microtubules

Which of these organelles carries out cellular respiration?

mitochondrion

Which organelle is the primary site of ATP synthesis in eukaryotic cells?

mitochondrion

Where is a bacterial cell's DNA found?

nucleoid region

The _____ is a selective barrier, regulating the passage of material into and out of the cell.

plasma membrane

A cell with a predominance of free ribosomes is most likely _____.

primarily producing proteins in the cytosol

What is a function of a bacterium's capsule?

protection

Large numbers of ribosomes are present in cells that specialize in producing which of the following molecules?

proteins

Which of the following is present in a prokaryotic cell?

ribosome

In a bacterium, where are proteins synthesized?

ribosomes

Which structure is the site of the synthesis of proteins that may be exported from the cell?

rough ER

Which of these organelles manufactures proteins bound for secretion out of the cell?

rough endoplasmic reticulum

The various parts of the endomembrane system serve different functions in the cell. In this activity, you will identify the roles of each part of the endomembrane system. Drag each function to the appropriate bin.

smooth ER: lipid synthesis, calcium ion storage, poison detoxification rough ER: protein synthesis Golgi apparatus: protein modification and sorting, cisternal maturation Iysosomes: macromolecule digestion, autophagy

Where is calcium stored?

smooth endoplasmic reticulum

Which type of organelle or structure is primarily involved in the synthesis of oils, phospholipids, and steroids?

smooth endoplasmic reticulum

You can recognize the process of pinocytosis when _____.

the cell is engulfing extracellular fluid

In a bacterium, we will find DNA in _____.

the nucleoid

Which organelle often takes up much of the volume of a plant cell?

vacuole

Which of these provides the cell with structural support?

D

Which of these is the double membrane that encloses the nucleus?

E

All proteins are synthesized by ribosomes in the cell. Some ribosomes float freely in the cytosol, while others are bound to the surface of the endoplasmic reticulum. Most proteins made by free ribosomes function in the cytosol. Proteins made by bound ribosomes either function within the endomembrane system or pass through it and are secreted from the cell. Which of the following proteins are synthesized by bound ribosomes? Select all that apply.

ER protein, insulin, lysosomal enzyme

Which of the following is a major difference between prokaryotic cells and eukaryotic cells?

Eukaryotic cells have more intracellular organelles than prokaryotes.

_____ are surface appendages that allow a bacterium to stick to a surface.

Fimbriae

Thylakoids, DNA, and ribosomes are all components found in _____.

chloroplasts

Proteins that are secreted from a eukaryotic cell must first travel through the endomembrane system. Drag the labels onto the diagram to identify the path a secretory protein follows from synthesis to secretion. Not all labels will be used.

endoplasmic reticulum -> cis Golgi cisternae -> medial Golgi cisternae -> trans Golgi cisternae -> plasma membrane

The evolution of eukaryotic cells most likely involved ________.

endosymbiosis of an aerobic bacterium in a larger host cell-the endosymbiont evolved into mitochondria

Which plant cell organelle contains its own DNA and ribosomes?

mitochondrion

Which structure is common to plant and animal cells?

mitochondrion

Ribosomal subunits are manufactured by the _____.

nucleolus

Which of these organelles produces H2O2 as a by-product?

peroxisome

A white blood cell engulfing a bacterium is an example of _____.

phagocytosis

Scientists can track the movement of proteins through the endomembrane system using an approach known as a pulse-chase experiment. This experiment involves 1) the "pulse" phase: Cells are exposed to a high concentration of a radioactively labeled amino acid for a short period to tag proteins that are being synthesized. 2) the "chase" phase: Any unincorporated radioactively labeled amino acids are washed away and large amounts of the same, but unlabeled, amino acid are added. Only those proteins synthesized during the brief pulse phase are radioactively tagged. These tagged proteins can be tracked through the chase period to determine their location in the cell. The data below were obtained from a pulse-chase experiment in which cells were examined at different times during the chase period. The numbers represent the radioactivity (measured in counts per minute) recorded at each of the indicated sites. The higher the number, the greater the radioactivity. (Table) Based on these data, what is the most likely function of the cells in this experiment?

phagocytosis

Plant cells and animal cells share many of the same structures, but each type of cell also has unique structures. In this activity, you will indicate which cell structures are found only in plant cells, only in animal cells, or in both plant and animal cells. Drag each cell structure to the appropriate bin. If a structure is found in both plant cells and animal cells, drag it to the "both" bin.

plant cell only: chloroplast, cellulose cell wall, central vacuole animal cell only: centriole both: mitochondrion, endoplasmic reticulum, Golgi apparatus, cytoskeleton, nucleus, plasma membrane

Drag the correct description under each cell structure to identify the role it plays in the plant cell.

plant cell wall = strong, protective structure made from cellulose fibrils central vacuole = regulates cytoplasm composition, creates internal pressure, and stores cell compounds chloroplast = makes sugar by converting light energy into chemical energy mitochondrion = produces chemical energy (ATP) that can power the cell Golgi apparatus = modifies and packages proteins

The _____ is the bacterial structure that acts as a selective barrier, allowing nutrients to enter the cell and wastes to leave the cell.

plasma membrane