Biology Chapter 6 Flashcards

Questions and Answers

What are the two different types of cells?

Prokaryotic

Neither A nor B

Eukaryotic

Both A and B (correct)

What is the plasma membrane?

A selective barrier that all cells contain.

Why do organisms generally have many cells, not smaller cells?

Cells increase in volume more than area, causing them to split before they get too large.

What is the fluid inside a cell?

Cytosol or cytoplasm. Signup and view all the answers

What are chromosomes?

Structures that carry genes in the form of DNA. Signup and view all the answers

What are ribosomes?

Organelles that make proteins. Signup and view all the answers

What are some differences between prokaryotic and eukaryotic cells?

<ol> <li>DNA location: prokaryotes don't have a nucleus. 2) Prokaryotes lack membrane-bound organelles. 3) Eukaryotes are more complex. 4) Eukaryotes are bigger. 5) Prokaryotes have flagella/fimbriae; eukaryotes do not.</li> </ol> Signup and view all the answers

What do prokaryotes have?

Fimbrae, nucleoid, ribosomes, plasma membrane, cell wall/capsule, flagella. Signup and view all the answers

What is the nucleoid?

The region in prokaryotes where the cell's DNA is stored, but is not enclosed. Signup and view all the answers

What are some differences between an animal cell and a plant cell?

Animal cells have centrioles, lysosomes, and ECM; plant cells have a central vacuole, chloroplasts, amyloplasts, cell wall, chlorophyll, and can photosynthesize. Signup and view all the answers

Cell membrane is also known as?

Plasma membrane. Signup and view all the answers

What are membranes usually made of?

A double layer of phospholipids, along with other lipids and proteins. Signup and view all the answers

What is the primary purpose of a cell membrane?

To control movement in and out of the cell, and define the cell from the outside environment. Signup and view all the answers

Which organelle has a single layer?

Both A and B Signup and view all the answers

What does a pore complex do in the nucleus?

Lines each pore and regulates the entrance and exit of proteins. Signup and view all the answers

Where else are genes located aside from the nucleus and why?

Mitochondria and chloroplasts; they are theorized to have once been free-living organisms incorporated into cells. Signup and view all the answers

What is the nuclear lamina?

A netlike array of protein filaments that maintain the shape of the nucleus. Signup and view all the answers

What is the nuclear matrix?

A network of fibers extending throughout the nuclear interior. Signup and view all the answers

DNA is located in?

Chromosomes, made up of chromatin (proteins and DNA). Signup and view all the answers

What is the nucleolus?

The site of rRNA synthesis, where ribosomal units are assembled. Signup and view all the answers

What are ribosomes made of?

Ribosomal RNA from the nucleolus and protein. Signup and view all the answers

What are the two types of ribosomes?

Free and bound. Signup and view all the answers

What are free ribosomes?

Ribosomes suspended in the cytosol, making proteins that function in the cytosol. Signup and view all the answers

What are bound ribosomes?

Ribosomes attached to the rough ER that make proteins for export or for use in membranes. Signup and view all the answers

Cells that specialize in protein secretion have a high proportion of what?

Bound ribosomes. Signup and view all the answers

Study Notes

Cell Types

Two main types of cells: eukaryotic (complex, with nucleus and organelles) and prokaryotic (simpler, smaller, without nucleus).

Plasma Membrane

All cells possess a plasma membrane that acts as a selective barrier for small, non-polar, uncharged substances.
As a cell grows, its volume increases disproportionately to its surface area, prompting division before it becomes too large.

Importance of Multicellularity

Organisms typically consist of multiple cells because increased volume necessitates cell division to maintain efficient function.

Cell Interior

The fluid within cells is known as cytosol or cytoplasm.

Chromosomes and Genes

Chromosomes carry genetic information encoded in DNA.

Ribosomes

Ribosomes function as organelles responsible for protein synthesis.

Prokaryotic vs. Eukaryotic Cells

Prokaryotic cells lack a nucleus, while eukaryotic cells have one, making them more complex.
Eukaryotic cells generally contain membrane-bound organelles, which prokaryotes lack.
Size difference: eukaryotic cells are typically larger.
Prokaryotic cells may have flagella or fimbriae, while eukaryotic cells do not.

Prokaryotic Cell Structures

Prokaryotes have structures such as:
- Fimbrae for surface movement
- Nucleoid region for unbound DNA
- Ribosomes for protein synthesis
- Plasma membrane, cell wall/capsule, flagella for movement.

Nucleoid

In prokaryotes, the nucleoid contains the cell's DNA but is not a membrane-bound compartment.

Animal vs. Plant Cells

Animal cells have centrioles, lysosomes, and extracellular matrix (ECM).
Plant cells have central vacuoles, chloroplasts, amyloplasts, cell walls, chlorophyll, and can perform photosynthesis.

Cell Membrane Composition

Also known as plasma membrane, it is primarily composed of a phospholipid bilayer, cholesterol, and proteins.

Function of Cell Membrane

The primary role is to regulate the movement of substances in and out of the cell, maintaining a distinct internal environment.

Organelles with Single Membranes

Lysosomes and peroxisomes (not part of the endomembrane system) have a single lipid bilayer.

Nucleus Structure and Function

The nucleus is part of the endomembrane system and houses the majority of the cell’s genetic material within a double membrane.
Pores allow for the transport of mRNA and proteins, regulated by pore complexes.

Gene Locations

Genes are also found in mitochondria and chloroplasts, suggesting evolutionary origins as independent organisms captured by eukaryotic cells.

Nuclear Lamina

This consists of a net-like arrangement of protein filaments that supports the nuclear shape.

Nuclear Matrix

The nuclear matrix is a network of fibers that extends throughout the nucleus, providing structural support.

Chromatin

DNA exists in the form of chromatin, a combination of DNA and proteins, found within chromosomes.

Nucleolus

The nucleolus synthesizes ribosomal RNA (rRNA), crucial for forming ribosomal subunits, and may have multiple instances within a nucleus.

Ribosome Composition

Ribosomes are made of rRNA and proteins, involved in synthesizing proteins by linking amino acids as per mRNA instructions.

Ribosome Types

There are two types of ribosomes: free (in cytosol, functioning locally) and bound (attached to the endoplasmic reticulum, producing proteins for export).

Specialization in Protein Secretion

Cells specialized for protein secretion typically have a higher proportion of bound ribosomes, facilitating the production of proteins for membranes or organelles.

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Test your knowledge on the key concepts from Biology Chapter 6 with these flashcards. Learn about the differences between eukaryotic and prokaryotic cells, as well as the role of the plasma membrane. This quiz provides an engaging way to reinforce your understanding of cellular biology.