Biology Chapter on Cell Structures

Questions and Answers

What is the primary role of DNA in the cell?

It stores and expresses genomic information. (correct)

It guides the synthesis of carbohydrates.

It functions as an enzyme in protein synthesis.

It facilitates the production of energy.

Where does RNA synthesis occur within a eukaryotic cell?

In the nucleus. (correct)

In the cytoplasm only.

In the mitochondria.

In the rough endoplasmic reticulum.

Which statement best describes the role of the nucleus in a cell?

It directs cell activities and contains the genetic material. (correct)

It is solely responsible for energy production.

It synthesizes lipids and proteins.

It provides structural support to the cell.

What happens during DNA replication?

The double helix unwinds and new strands are formed. Signup and view all the answers

Which cellular component performs the function of protein synthesis?

Ribosomes. Signup and view all the answers

What occurs during the S Phase of the cell cycle?

The cell replicates its entire genome. Signup and view all the answers

Which organelle is primarily responsible for synthesizing membrane lipids and secretory proteins?

Endoplasmic Reticulum Signup and view all the answers

What is the function of the nucleolus within the cell?

Synthesizes ribosomes and RNA for protein assembly. Signup and view all the answers

What is the main role of lysosomes in the cell?

To degrade and recycle cellular debris. Signup and view all the answers

During which phase of mitosis are replicated chromosomes condensed and made visible?

Prophase Signup and view all the answers

What prevents the entry of pathogens into the cell?

Glycocalyx Signup and view all the answers

Which statement correctly describes the role of ribosomes?

They synthesize proteins needed by the cell. Signup and view all the answers

What is the primary function of peroxisomes?

Oxidative detoxification Signup and view all the answers

In which cell cycle phase does the cell synthesize additional proteins required for mitosis?

G2 Phase Signup and view all the answers

Which of the following best describes an effect of a mutation in the genes coding for ribosomal RNA?

Impaired protein synthesis. Signup and view all the answers

How does the nuclear membrane regulate transport?

Through specific openings that control material entry and exit. Signup and view all the answers

Which statement about microtubules is true?

They help maintain cellular organization and assist in cell division. Signup and view all the answers

What process does the Golgi apparatus primarily facilitate?

Modification and transport of proteins Signup and view all the answers

What is a key difference between somatic cells and germ cells?

Somatic cells have two copies of the genome, while germ cells have one. Signup and view all the answers

Which type of epithelial tissue is characterized by a single layer of column-like cells?

Simple columnar epithelial tissue Signup and view all the answers

In which type of cell are organelles vital for performing specific functions absent?

Prokaryotic cells Signup and view all the answers

Which of the following describes the process of self-renewal in stem cells?

Stem cells divide to create more stem cells as well as differentiated cells. Signup and view all the answers

Which type of connective tissue provides insulation and energy storage in the body?

Adipose tissue Signup and view all the answers

Study Notes

Genetic Inheritance

Maternal allele: inherited from mother
Paternal allele: inherited from father

Nucleolus

Located inside the nucleus
Contains RNA needed for protein synthesis
Major site of ribosome subunit assembly

Nuclear Membrane

Encloses the nucleus
Composed of a bilayer membrane
Contains openings for material exchange with the cytoplasm

Glycocalyx

Gel-like meshwork surrounding the cell
Acts as a physical barrier, preventing pathogen entry
Composed of glycoproteins and glycolipids

Mitochondria

Known as the powerhouse of the cell
Generates ATP through the TCA cycle
Surrounded by two membranes: outer (lipid bilayer) and inner (protein-rich)

Endoplasmic Reticulum (ER)

Comprises interconnected membrane complexes
Extends from the cell membrane to surrounding organelles
Rough ER: Contains ribosomes; synthesizes membrane lipids and secretory proteins
Smooth ER: Lacks ribosomes; involved in lipid synthesis and protein transport

Golgi Apparatus

Responsible for sugar formation and protein modification
Cis side (proximal): Receives proteins from the ER
Trans side (distal): Releases modified proteins via secretory vesicles

Ribosomes

Essential for protein synthesis in cells
Provide structural support and catalyze biochemical reactions
Synthesis occurs in cytoplasm, nucleolus, and nucleoplasm

Lysosomes

Involved in degrading cellular debris and recycling content
Contain proteolytic enzymes for digestion
Autolysis occurs if the lysosomal membrane ruptures, leading to cell death

Peroxisomes

Detoxify various molecules and break down substances
Known as microbodies
Carry out oxidation reactions producing H2O2, which is then broken down by catalase

Cytoskeleton

Provides structural support for organelles and cell integrity
Composed of protein rods and tubules
Microtubules: Form spindles for cell division; maintain organization
Microfilaments: Generate internal cellular force

Cell Division and Death

The cell cycle describes the sequence of cell division events, consisting of interphase and mitosis

Interphase

Major phase of cellular function; includes DNA and organelle replication
Divided into G1, S (synthesis), and G2 phases
Cells can enter a resting phase called G0 from G1

G1 Phase

Resumes synthesis of proteins, lipids, and carbohydrates
Duration varies significantly among different cell types, commonly lasts 10-11 hours

S Phase

Entire genome replication; chromosomes consist of two DNA copies called sister chromatids, joined at the centromere
Lasts about 8-10 hours

G2 Phase

Occurs post-DNA replication; protein synthesis continues
Lasts approximately 4 hours

Mitosis

The replicated chromosomes condense to become visible
Comprised of four phases: Prophase, Metaphase, Anaphase, Telophase

Prophase

DNA coils tightly, shortening and thickening chromosomes
Nuclear membrane disintegrates

Anaphase

Microfilament bonds form, leading to chromosome separation

Chemical Constituents

Carbohydrates: Provide energy and support cell structure
Lipids: Form membranes, hormones; store energy
Proteins: Involved in clotting and muscle contraction; major connective tissue component
Nucleic Acids: Store and express genetic information

Nucleus

Control center of the cell, directing activities
Separated from cytoplasm by the nuclear membrane
Houses genetic material (DNA) involved in replication and transcription

DNA Structure

Resembles a double helix, similar to a spiral staircase

Cell Types

Somatic Cells: Diploid cells containing two genome copies
Germ Cells: Haploid sperm and egg cells, each having one genome copy
Stem Cells: Diploid cells that self-renew and differentiate

Primary Tissue Types

Epithelial, Connective, Muscular, Nervous

Epithelial Tissue Classification

By Cell Shape: Squamous, Cuboidal, Columnar
By Layer Number: Simple, Pseudostratified, Stratified, Transitional

Prokaryotic vs Eukaryotic Cells

Prokaryotic Cells: Lack a nucleus; DNA is unbound
Eukaryotic Cells: Contain organelles that perform specific cellular functions

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Description

This quiz covers key concepts related to cell structures, including the nucleolus, nuclear membrane, and glycoprotein layer. Test your knowledge on how these components function within a cell and contribute to its overall health and activity. Ideal for students studying cell biology in detail.