ISB 202 Appl Envir and Organismal Biology Chapter 3

Of these, which solution could be in the beaker that contains the hypertonic solution?

4% (m/v) NaCl solution isotonic flows equally (looks unchanged) hypertonic flows outwards (looks shriveled or exploded) hypotonic flows in (looks like sucking in)

Which statements describe examples of facilitated diffusion?

A kidney cell absorbs water molecules down their concentration gradient using a membrane protein; An inner ear hair cell allows potassium ions to flow down their concentration gradient after sound waves stimulate a membrane protein; A neuron allows potassium ions to leave the cell down their concentration gradient using a membrane channel

A) A biological membrane is a bilayer that contains lipids with B) Which of these are components of biological membranes? C) How are biological membranes held together?

A) hydrophilic head groups oriented toward the solvent (extracellular fluid and cytosol) and hydrophobic tail groups pointing inward. B) proteins, lipids C) hydrophobic interactions

Which tenet of cell theory is described by the paragraph about the historical observations of cells?

All organisms are composed of one or more cells.

Bacteria are grouped as either gram‑positive or gram‑negative. Which features are found in gram‑positive bacteria, and which are found in gram‑negative bacteria?

Gram-Positive: have thick cell walls; have no membrane on the outside of cell walls; belong to a single phylum; have lipoteichoic acid that anchors the cell walls to the cell membranes Gram-Negative: have thin cell walls; have membranes of lipopolysaccharides on the outer side of cell walls; found in many phyla

Which statements about lysosomes are true?

Lysosomes occasionally break down healthy cells; Lysosomes are membrane spheres containing digestive enzymes; Lysosomes break down damaged organelles for recycling

Cells are categorized as either prokaryotic or eukaryotic. Classify the characteristics as being unique to prokaryotic cells, common to both cell types, or unique to eukaryotic cells. Move each description into the correct category.

Prokaryotic Cells: relatively small, typically less than 10 um in size; lack a true cytoskeleton Both: contain DNA; use ribosomes to synthesize proteins Eukaryotic cells: nuclear membrane surrounds DNA

A cell uses many methods to transport solutes across the plasma membrane. Classify the descriptions as either simple diffusion, facilitated diffusion, active transport, or bulk transport.

Simple diffusion: movement of solutes into the cell directly through the plasma membrane Facilitated diffusion: movement of solutes into the cell down their concentration gradient using membrane proteins Active transport: movement of solutes into the cell against their concentration gradient using membrane proteins Bulk transport: movement of contents of transport vesicles into the cell by endocytosis

Which statements describe facilitated diffusion?

Small, charged molecules and ions move down their concentration gradient out of a cell through proteins in the plasma membrane; Solutes move across the membrane down their concentration gradient through specialized membrane proteins

Which statements are properties of protein‑based active transport?

Substances move from an area of lower concentration to an area of higher concentration; The cell spends energy to move substances through a protein across the plasma membrane

Based on cell theory, what statements can confidently be made regarding these unidentified plants and seeds?

The cells in the seeds are still alive, so they produced new plant cells; Tissues in both the plants and the seeds are made of cells.

Which choice describes diffusion?

The movement of a substance down a concentration gradient from an area of high concentration to an area of low concentration

Select the descriptions that apply to the ribosome.

a cellular structure that is responsible for the synthesis of proteins; a cellular structure that is composed of both RNA and protein

Select the specific mechanisms by which certain antibiotics interfere with translation.

binds to the 50s ribosomal subunit; binds to the ribosome and blocks subsequent translation

Which eukaryotic cell parts is found in the cytoplasm, transports organelles from one location within the cell to another, and is composed of interconnected protein fibers?

cytoskeleton

Which of the statements are true of endosymbiotic theory?

explains the origin of some eukaryotic organelles, such as chloroplasts; explains why mitochondria contain their own genetic information; states that an ancestral eukaryotic cell engulfed an aerobic protobacteria

Place the appropriate plant cells in the isotonic, hypertonic, and hypotonic beakers

isotonic: water flows equally (looks unchanged) hypertonic: water flows out (looks shriveled) hypotonic: water flows in (looks swollen)