Biology: Cell Structure and Function Quiz

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Questions and Answers

What is a key property common to all cells?

Existence of a nucleus

Ability to move independently

Presence of a cell membrane (correct)

Ability to produce energy through photosynthesis

How does the surface-to-volume ratio affect cell size?

Larger cells can more efficiently perform metabolic functions

Smaller cells have a lower surface-to-volume ratio

Larger cells have a higher surface-to-volume ratio

Increased surface area can facilitate nutrient absorption (correct)

Which of the following correctly distinguishes prokaryotic from eukaryotic cells?

Prokaryotic cells have a defined nucleus; eukaryotic cells do not.

Prokaryotic cells possess membrane-bound organelles; eukaryotic do not.

Eukaryotic cells lack ribosomes; prokaryotic cells contain them.

Eukaryotic cells are typically larger than prokaryotic cells. (correct)

Which evidence supports the endosymbiotic theory of eukaryotic organelles?

Mitochondria and chloroplasts possess their own DNA. Signup and view all the answers

What features must have been present in the earliest cells?

Simple genetic material capable of replication Signup and view all the answers

What is the primary function of mitochondria in eukaryotic cells?

Generate ATP using oxygen and glucose Signup and view all the answers

Which statement about the cytoskeleton is true?

It supports the shape of the cell and keeps organelles in fixed locations. Signup and view all the answers

How are mitochondria inherited?

From the mother only Signup and view all the answers

What are intermediate filaments primarily known for?

Providing structural stability and durability to cells Signup and view all the answers

Which type of structure is responsible for cellular propulsion, similar to that of a spaceship?

Cilia and Flagella Signup and view all the answers

What role do lysosomes play in cellular maintenance?

They digest and remove old structures and organelles. Signup and view all the answers

What is a primary by-product of the activities of peroxisomes?

Hydrogen peroxide Signup and view all the answers

Which structure is responsible for ATP production in the cell?

Mitochondria Signup and view all the answers

What feature distinguishes peroxisomes from lysosomes?

Peroxisomes oxidize fatty acids while lysosomes digest cellular debris. Signup and view all the answers

What is the significance of the low pH inside lysosomes?

It activates the digestive enzymes. Signup and view all the answers

What is the primary function of cilia and flagella in eukaryotic cells?

Motion Signup and view all the answers

Which structure is primarily associated with the movement of chromosomes during cell division?

Centrosome Signup and view all the answers

What is the arrangement of microtubules in cilia and flagella referred to as?

9 + 2 structure Signup and view all the answers

What type of organelle contains chlorophyll and is involved in photosynthesis?

Chloroplasts Signup and view all the answers

Which of the following is NOT a function of the vacuole in plant cells?

Regulating cell division Signup and view all the answers

What protein is responsible for the movement of microtubules in cilia and flagella?

Dynein Signup and view all the answers

How do flagella move in eukaryotic cells?

By undulating Signup and view all the answers

Which of the following structures is unique to plant cells?

Water vacuole Signup and view all the answers

What is the primary role of the Golgi Complex in a cell?

Collection, packaging, and distribution of proteins and lipids Signup and view all the answers

Which structure serves as the 'recycling truck' of the cell?

Lysosome Signup and view all the answers

What distinguishes eukaryotic cells from prokaryotic cells?

Presence of the endomembrane system Signup and view all the answers

What are the two types of transport associated with vesicles?

Endocytosis and exocytosis Signup and view all the answers

What is the structure of the Golgi Complex?

Flat membranes with bulging edges Signup and view all the answers

What is the primary product of nitrogen fixation that makes nitrogen bioavailable to plants?

Ammonia (NH3) Signup and view all the answers

Where is the cis face of the Golgi Complex located?

Near the Rough Endoplasmic Reticulum Signup and view all the answers

Which characteristic is NOT associated with mitochondria according to the endosymbiosis theory?

Ability to photosynthesize Signup and view all the answers

Glycoproteins are formed by the addition of which molecule?

A polysaccharide Signup and view all the answers

What type of vesicles would be used for exporting materials out of the cell?

Exocytic vesicles Signup and view all the answers

How does RNA serve a crucial role in early life forms?

It can catalyze chemical reactions. Signup and view all the answers

What role do vesicles play in intracellular transport?

Transporting materials within the cell Signup and view all the answers

What is NOT a characteristic of prokaryotic cells?

Presence of a nucleus Signup and view all the answers

Which statement accurately describes ribozymes?

They are RNA molecules that act as enzymes. Signup and view all the answers

How many Golgi Complexes might a protist typically have?

One to a few Signup and view all the answers

What key role do cell membranes play in cellular environments?

They separate the internal and external environment of the cell. Signup and view all the answers

What evidence supports the endosymbiosis theory for the origin of mitochondria?

Mitochondria can replicate independently. Signup and view all the answers

Which of the following processes includes the conversion of nitrogen gas (N2) into a usable form for living organisms?

Nitrogen fixation Signup and view all the answers

Why is DNA loosely compacted during interphase?

To make it readable by the cell Signup and view all the answers

What role do histones play in the structure of nucleosomes?

They help in the condensation of chromosomes Signup and view all the answers

What is the advantage of chromatin being maximally compacted during cell division?

It enables efficient partitioning to daughter cells Signup and view all the answers

What does the term TADs refer to in the context of chromatin organization?

Topologically associated domains Signup and view all the answers

How are nucleosomes structured?

DNA duplex coiled around histone proteins Signup and view all the answers

During which phase of the cell cycle are chromosomes most condensed?

M phase Signup and view all the answers

What is the structural unit of DNA packaging called?

Nucleosome Signup and view all the answers

What occurs to homologous chromosomes prior to DNA replication?

They consist of one DNA molecule each Signup and view all the answers

What is the purpose of cohesin proteins during DNA replication?

They bind sister chromatids together. Signup and view all the answers

During which phase does the cell synthesize a replica of its genome?

S Phase Signup and view all the answers

What is primarily occurring during the G1 phase of interphase?

Cell growth and organelle duplication occur. Signup and view all the answers

What is the outcome at the end of the somatic cell division process?

Two identical daughter cells are formed. Signup and view all the answers

What distinguishes the mitotic phase from interphase?

Sister chromatids are separated during the mitotic phase. Signup and view all the answers

In what state is DNA during interphase?

Loosely compacted and not clearly defined. Signup and view all the answers

Which statement is true regarding the centromere?

It connects sister chromatids during cell division. Signup and view all the answers

Which phase is primarily characterized as the longest stage of the cell cycle?

G1 Phase Signup and view all the answers

What is the main method of bacterial cell division?

Binary fission Signup and view all the answers

What happens during the replication of a bacterial chromosome?

It is replicated in two directions Signup and view all the answers

Which of the following correctly describes the outcome of binary fission in bacteria?

A clone of the original cell is produced Signup and view all the answers

How is bacterial DNA compacted within the cell?

Through a process called supercoiling Signup and view all the answers

What structure forms to separate the two new cells during bacterial division?

Septum Signup and view all the answers

What is the location of bacterial DNA within a cell known as?

Nucleoid region Signup and view all the answers

Which phase of the eukaryotic cell cycle is primarily responsible for DNA replication?

S phase Signup and view all the answers

In contrast to eukaryotic cell division, what is a key characteristic of bacterial cell division?

Clonal reproduction Signup and view all the answers

What is the term for a cell with two sets of homologous chromosomes?

Diploid Signup and view all the answers

Which type of cell division do somatic cells undergo?

Mitosis Signup and view all the answers

Which of the following correctly defines germ-line cells?

Diploid cells that undergo meiosis to produce haploid gametes Signup and view all the answers

How many chromosomes do humans have in diploid somatic cells?

46 Signup and view all the answers

What does the term 'ploidy' refer to in genetics?

The number of sets of homologous chromosomes Signup and view all the answers

Which of the following statements is true about haploid cells?

They have one set of chromosomes. Signup and view all the answers

In what way do offspring inherit genetic material from their parents?

From a combination of both parents' chromosomes Signup and view all the answers

Which feature distinguishes somatic cells from germ-line cells?

Somatic cells undergo mitosis, while germ-line cells undergo meiosis Signup and view all the answers

What initiates the anaphase during somatic cell division?

Centromeres splitting due to cohesion protein removal. Signup and view all the answers

Which of the following occurs during telophase?

Two daughter nuclei form. Signup and view all the answers

Which phase of mitosis is characterized by the alignment of chromosomes on the metaphase plate?

Metaphase Signup and view all the answers

What is the role of the cleavage furrow during cytokinesis in animal cells?

Pinching the cell into two identical daughter cells. Signup and view all the answers

What occurs during the G1 phase of the cell cycle?

Cells may enter a resting state called G0 Signup and view all the answers

How do plant cells differ from animal cells during cytokinesis?

Plant cells assemble a membrane using vesicles. Signup and view all the answers

What happens to the chromosomes at the end of anaphase?

They migrate to opposite poles. Signup and view all the answers

Which of the following describes a characteristic of prophase in mitosis?

Nuclear envelope disassembly begins Signup and view all the answers

Which structure is responsible for the movement of chromosomes during cell division?

Kinetochore microtubule Signup and view all the answers

What happens during cytokinesis?

Cytoplasm is divided into two daughter cells Signup and view all the answers

What feature characterizes the end of metaphase?

Chromosomes line up at the metaphase plate. Signup and view all the answers

Which phase of the cell cycle typically sees the most variation in length between different cell types?

G1 phase Signup and view all the answers

During which phase do microtubules attach to the centromeres of chromosomes?

Prometaphase Signup and view all the answers

Which statement is true about the frequency of cell division?

Neurons do not appear to divide after maturity Signup and view all the answers

What is indicated when a cell is in the G0 phase?

It may resume division after a long pause Signup and view all the answers

Which role do centrioles play during mitosis?

They form the spindle apparatus Signup and view all the answers

What is the first step in Mendel's experimental method?

Produce true-breeding strains for each trait Signup and view all the answers

Which of the following traits did Mendel study in his experiments?

Seed shape Signup and view all the answers

What is the result of crossing a true-breeding purple flower with a true-breeding white flower?

Offspring will have only purple flowers Signup and view all the answers

What process did Mendel use to prevent self-fertilization in his pea plants?

Removing the anthers from flowers Signup and view all the answers

How many different traits did Mendel produce true-breeding strains for?

7 Signup and view all the answers

Which of these is NOT a method included in Mendel's experimental method?

Alter the genetic material artificially Signup and view all the answers

What is the purpose of counting the number of offspring in Mendel's experiments?

To calculate the inheritance pattern of traits Signup and view all the answers

What do true-breeding strains guarantee in Mendel's experiments?

Uniformity in trait expression over generations Signup and view all the answers

What is a key characteristic of a test cross?

It involves crossing a dominant phenotype with a homozygous recessive. Signup and view all the answers

In a monohybrid cross, what is being studied?

Variations of a single trait. Signup and view all the answers

During a dihybrid cross, what is the key purpose?

To observe the inheritance of two separate traits. Signup and view all the answers

What is the expected phenotype of the F1 generation in a dihybrid cross?

Only dominant phenotypes for each trait. Signup and view all the answers

Which genotype represents a heterozygous individual?

Pp Signup and view all the answers

How many gametes can a dihybrid plant with the genotype RrYy produce?

4 Signup and view all the answers

What is the term used to describe true breeding parental generations in genetic crosses?

P generation Signup and view all the answers

In a Punnett square, what do the letters represent?

The alleles of the offspring. Signup and view all the answers

What is the genotype of the F1 generation offspring when crossing a true-breeding purple parent with a true-breeding white parent?

Pp Signup and view all the answers

In a Punnett square, which type of allele expresses itself over the other?

Dominant allele Signup and view all the answers

What phenotypes are possible in the F2 generation resulting from a cross of F1 heterozygous purple offspring?

Purple and white Signup and view all the answers

What percentage of F2 offspring from a Pp x Pp cross are expected to be homozygous recessive (pp)?

25% Signup and view all the answers

What type of gametes do true-breeding parents produce?

One type of gamete Signup and view all the answers

Which phenotype corresponds with the homozygous dominant genotype?

Homozygous purple flowers Signup and view all the answers

Why are all F1 offspring purple when crossing a purple and a white parent?

The dominant trait completely masks the recessive trait Signup and view all the answers

What is the expected ratio of phenotypes in the F2 generation from a dihybrid cross?

3:1 Signup and view all the answers

What ratio of dominant to recessive traits is observed in the F2 generation from self-fertilized hybrid offspring?

3:1 Signup and view all the answers

What ratio represents the typical genetic makeup of the F3 generation?

1:2:1 Signup and view all the answers

What is the definition of a dominant allele?

An allele that is always expressed in the phenotype Signup and view all the answers

What does it mean when an organism is described as homozygous?

Having two identical alleles for a specific gene Signup and view all the answers

Which statement about alleles is true?

Alleles remain discrete and do not blend with one another Signup and view all the answers

What does the term phenotype refer to?

The physical appearance of an organism Signup and view all the answers

In Mendel's experiments, how were alternative traits expressed in the progeny of a particular cross?

In the ratio of 3:1 Signup and view all the answers

Which of the following statements accurately summarizes Mendel's five-element model of inheritance?

Alleles are inherited in pairs, but not as blends Signup and view all the answers

What color flowers are produced in the first filial generation (F1) when a true-breeding purple flower is crossed with a true-breeding white flower?

Only purple flowers Signup and view all the answers

What does the term 'dominant trait' refer to in the context of genetics?

A trait that is always expressed in hybrid offspring Signup and view all the answers

What phenotypic ratio is expected in the F2 generation after self-fertilizing hybrid F1 plants?

3:1 ratio of purple to white Signup and view all the answers

What is observed when conducting a reciprocal cross between two true-breeding plants?

Same offspring phenotype regardless of the cross direction Signup and view all the answers

Which statement accurately differentiates hybrid offspring from their true-breeding parents?

Hybrids display one parent's trait exclusively Signup and view all the answers

How is the recessive trait treated in the F1 generation when true-breeding strains are crossed?

Completely masked and not expressed Signup and view all the answers

What is the role of self-fertilization in the F1 generation for producing the F2 generation?

To stabilize the traits of the F1 hybrid Signup and view all the answers

What phenomenon is completely absent in the offspring of the initial cross between two true-breeding plants?

Identification of intermediate characteristics Signup and view all the answers

What is the primary purpose of a test cross in genetics?

To determine the unknown genotype of an individual Signup and view all the answers

What does a purple-flowered pea plant's phenotype indicate?

The plant may be either homozygous or heterozygous. Signup and view all the answers

In a test cross, what genotype is the unknown genotype crossed with?

Homozygous recessive Signup and view all the answers

Which Punnett square outcome would indicate that a purple-flowered plant is likely homozygous?

100% purple flowers Signup and view all the answers

What genetic feature allows a plant with the purple phenotype to potentially be heterozygous?

The dominance of the purple allele Signup and view all the answers

What conclusion can be made if a test cross results in offspring with a mix of purple and white flowers?

The unknown plant is heterozygous. Signup and view all the answers

In the context of Mendelian genetics, how is the term 'homozygous' best defined?

Having identical alleles for a trait Signup and view all the answers

What type of genetic cross demonstrates the principle of segregation in inheritance?

Monohybrid cross Signup and view all the answers

Study Notes

General Biology 1 - Fall 2024

Course focusing on the study of cells, as part 2.
Textbook used: Raven, Biology, 13th edition.
Key topics covered by these notes include Cell Structure, Chemical Basis of Life, Organelles, Endomembrane System, the Golgi Complex, Vesicles, Lysosomes and Peroxisomes, Mitochondria, Cytoskeleton, Cilia and Flagella, Centrosomes, Plant cells and Vacuoles, Chloroplasts, how life began on Earth, prokaryotes and eukaryotes (differences).

Chemical Basis of Life

Cell Theory Summary: Summarize the Cell Theory and list the key properties common to all cells.
Surface Area to Volume Ratio: Discuss the impact of surface-to-volume ratios on cell size, and biological processes in general.
Prokaryotic vs. Eukaryotic Cells: Distinguish between prokaryotic and eukaryotic cells.
Cellular Structures: Identify and/or explain the function of various cellular structures (organelles) found in typical eukaryotic cells.
Cell Comparison: Compare the structural aspects of cells found in bacteria, protists, plants, animals, and fungi.
Origins of Life: Briefly discuss the possible origins of life, and the properties of life.
Early Cells: Describe features that must have been present in the earliest cells.
Endosymbiotic Theory: Describe the endosymbiotic theory regarding eukaryotic organelles, including evidence supporting the theory.

Organelles

The cell is like a medieval city.
Organelles are like all the buildings of a city.
The endomembrane system is a series of membranes within the cytoplasm of a eukaryotic cell.

Endomembrane System

The endomembrane system is a series of membranes throughout the cytoplasm (surrounds the organelles).
It divides the cell into compartments where different cellular functions occur.
The presence of endomembrane is a fundamental distinction between eukaryotes and prokaryotes.
- Components include control center (nucleus), assembly line (endoplasmic reticulum), workbenches (ribosomes), distribution center (Golgi complex), and cleaning crew (lysosomes).

Golgi Complex

Function: Collection, packaging, and distribution of proteins and lipids; modification of proteins and lipids.
Number: Protists: 1 to a few, Animals: >20, Plants: >100.
Structure: Flattened membranes with bulging edges. Two key faces: cis (receiving) and trans (exit) faces.

Vesicles

Structure: Small membrane sacs made of a phospholipid bilayer.
Function: Transporting materials within the cell. Transport material "in and out" of the cell.
Types of Transport: Endocytosis (import into cell) and exocytosis (export from cell).

Cell structure: Lysosomes and Peroxisomes

Lysosomes: Small round vesicles that arise from the Golgi apparatus, functioning as the cell's recycling centers. Contain enzymes that break down waste, old structures, and organelles. Key to having a low internal pH to activate digestive enzymes.
Peroxisomes: Similar to lysosomes but smaller; involved in oxidizing fatty acids and some amino acids generating hydrogen peroxide; contain catalase to break down hydrogen peroxide.

Cell structure: Mitochondria

Structure: Rod-shaped organelles with two membranes (outer and inner); inner membrane folds into cristae; matrix (innermost part) contains DNA and ribosomes.
Function: Powerhouses of the cell, generating ATP (energy currency); use oxygen and glucose for energy production, producing CO2 and water.
Fun Facts: Mitochondria have their own DNA (mtDNA), can divide independently, and are inherited only from the mother.

Cytoskeleton

Structure: Network of protein fibers found in all eukaryotic cells.
Function: Supports cell shape; keeps organelles in fixed locations.
Types: Actin filaments (also called microfilaments), Microtubules, Intermediate filaments.

Cilia and Flagella

Function: Both are used for cell motion; cilia are more numerous and shorter; flagella more lengthy and are few, if any in a single cell.
Examples: Sperm tails (flagella). Cilia can be found in the respiratory tract or uterine tubes to move substances.
Structure: Nine pairs of microtubules surrounding two central microtubules, a 9 + 2 arrangement. Dynein proteins cause microtubules to move.

Centrosome

Structure: Pair of centrioles arranged perpendicularly to each other.
Function: Involved in cell division, specifically movement of chromosomes to cell ends during cell division.

Plant Cells

Special Structures: Central vacuole, Cell wall (peptidoglycan), Chloroplasts (photosynthesis), No centrioles.
Vacuole: Function in storage of sugars, salts, and pigments; waste disposal; and maintenance of water balance. The vacuolar membrane is called the tonoplast and contains channels for water.
Chloroplast: Two membranes surrounding the organelle; contain chlorophylls for photosynthesis; have their own DNA and ribosomes; involved in photosynthesis, converting light energy to chemical energy.

How Life Began on Earth

Metabolic Evolution Landmarks: Oxygenic photosynthesis; carbon fixation (12C isotope).
Nitrogen Fixation: Nitrogen gas (N₂) is essential for life (DNA, amino acids), but unavailable to most organisms; nitrogen fixation is a vital process by microbes creating usable nitrogen for plants and other organisms to use.
RNA Hypothesis: Earliest life may have used RNA as the primary informational molecule, as RNA can store genetic information, act enzymatically in ribozymes, and form ribosomal structures.
Cell Membranes: These are crucial for separating the internal environment from the external environment, and are vital in increasing the probability of biochemical reactions.

Mitochondria Endosymbiosis Theory

Capture of Ancestral Bacteria: Mitochondria may have originated from aerobic bacteria that were engulfed by an ancestral eukaryotic cell.
Evidence: Double membrane structure (outer from host, inner from bacteria); contain their own DNA and ribosomes; can multiply independently.

Chloroplast Endosymbiosis Theory

Capture of Photosynthetic Bacteria (secondary): Chloroplasts may have originated from photosynthetic bacteria that were engulfed by an ancestral eukaryotic cell.
Evidence: Double membrane structure (inner from host, outer from bacteria); contain their own DNA and ribosomes; can multiply independently.
Secondary Endosymbiosis: Involves an additional engulfing event between eukaryotic cells further supporting the theory

Endosymbiosis Theory

Proposing that mitochondria and chloroplasts were originally bacteria that were engulfed by a larger cell.

Prokaryotes

Prokaryotes vs. Eukaryotes Differences: In summary, Prokaryotes lack a membrane-bound nucleus and other organelles, generally are smaller in size, and contain a single circular DNA molecule. Eukaryotes have a membrane-bound nucleus, more complex organelles, and multiple linear chromosomes.
Characteristics: Prokaryotes are the simplest organisms. They lack nuclei and other membrane-bound organelles.
Bacterial Cell Walls: The majority of bacterial cell walls incorporate peptidoglycan, a unique polymer that aids in preserving the bacterial cell's shape and resisting the uptake or loss of water. This differs from peptidoglycan which is present in plants and fungi.
Archaeal Cell Walls: Differing from bacteria, archaea lack peptidoglycan and their cell wall structures vary greatly. The membrane lipids are made from a different chemical structure.
Prokaryotic Flagella: Flagella help in cell motion. It's a rotary motor across the plasma membrane using energy from proton gradients.

Difference Between Prokaryotes and Eukaryotes

Eukaryotes possess: membrane-bound nucleus, complex endomembrane system and compartmentalization, and cytoskeleton.

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Description

Test your knowledge on key properties common to all cells, the differences between prokaryotic and eukaryotic cells, and the roles of various organelles such as mitochondria and lysosomes. This quiz also covers important theories like the endosymbiotic theory and cellular maintenance mechanisms.