Bio120 Test 2

Characteristics of Eukaryotic Cells

* DNA in a nucleus that is bound by a double membrane
* Membrane-bound organelles
* Cytoplasm in the region between plasma membrane and nucleus

Characteristics of Prokaryotic Cells

* no nucleus
* DNA is in an unbounded region called the nucleoid
* No membrane-bound organelles
* Cytoplasm bound by the plasma membrane

Basic features of a cell:

* Plasma membrane
* Semifluid substance called cytosol
* Chromosomes
* Ribosomes

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Function of the nucleoid

* essential for controlling the activity and reproduction
* DNA is stored in an unbounded region
* Binds DNA and makes its shape

Function of the nuclear pores:

a large complex of proteins that allows small molecules and ions to freely pass, or diffuse, into or out of the nucleus.

Function of the mitochondria

Energy creation (Atp)

Chemical energy conversion

Endomembrane System

* Nuclear envelope 
* Endoplasmic reticulum 
* Golgi apparatus 
* Lysosomes
* Plasma membrane

what does the endomembrane system do

transports proteins from the site of synthesis to its final destination inside or outside the cell

What are the properties of plasma membrane proteins

amphipathic, diverse and selective

Amphipathic meaning

they have both hydrophilic and hydrophobic regions

Diverse meaning (plasma membrane proteins)

they have various functions, including transport, enzyme activity, and cell signaling

Selective meaning (plasma membrane proteins)

what they allow to pass through the membrane

What is the role of carbohydrates on the plasma membrane?

they serve as cell markers and allow cells to recognize each other.

What types of molecules can diffuse through cell membranes?

small hydrophobic molecules

What is passive transport?

does not require energy and occurs along a concentration gradient

What is active transport?

requires energy and can occur against a concentration gradient.

What is the concentration gradient

the concentration of particles within a cell

Phagocytosis

the process by which cells engulf and digest particles or other cells

Lysosomes

involved in the digestion of the particles

Pintocytosis

the process by which a cell engulfs fluid

Receptor-mediated endocytosis

the uptake of specific molecules that bind to receptors on the plasma membrane

DNA synthesis and replication

The double-stranded DNA molecule separates, and each strand serves as a template for the synthesis of a new complementary strand. The result is two identical DNA molecules.

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Chromosomes to sister chromatids

What part of the cell cycle DNA synthesis occurs

S phase

The center location of the sister chromatids that attaches to the spindle fibers

centromere

How many centromeres per sister chromatid

One centromere

What is the shape of the centromere

shape of an X

Cell Cycle Order

G1 → S → G2 → Mitosis → Cytokenesis

G1 phase description

first gap in cell cycle

S phase description

When synthesis takes place

G2 phase

second gap in cell cycle

Where are chromosomes duplicated

only in the S phase

What are the 5 stages of mitosis

* Prophase
* prometaphase
* metaphase
* anaphase
* telophase

First stage of mitosis

prophase

Second stage of mitosis

prometaphase

Third stage of Mitosis

metaphase

4th stage of mitosis

anaphase

5th stage of mitosis

telophase

what takes place after mitosis in the cell cycle?

cytokinesis

Nomenclature of the “pole” of the cell structure involved in mitotic spindle fiber formations

centrosome

What is the role of the mitotic spindles (microtubules) during mitosis?

they are responsible for separating the sister chromatids during mitosis

what are mitotic spindles made of?

microtubules

How do the mitotic spindles separate the sister chromatids

They attach to the centromeres of the chromosomes and pull them apart, ensuring that each daughter cell receives a complete set of chromosomes.

What is the defining feature of metaphase

the chromosomes align along the equatorial plane of the cell

Which of the following areas in bacterial cells best \n describes where chromosomal DNA is generally localized?

In the nucleoid

While abundant quantities of proteins are produced by free \n ribosomes in the cytosol, new proteins are also produced by \n which of the following organelles?

mitochondria

Which of the following statements best describes a \n characteristic feature of integral membrane proteins?

They are amphipathic, with at least one hydrophobic \n region

Which of the following types of molecules will diffuse through \n a cell membrane most readily?

small hydrophobic molecules

The force driving simple diffusion is ________, while the \n energy source for active transport is ________.

a concentration gradient; ATP hydrolysis

After DNA replication, each duplicated chromosome consists \n of two of which of the following structures?

sister chromatids

In a diploid cell with four chromosome pairs (2n = 8), how \n many centromeres will be found in a nucleus at G2 of the cell \n division cycle?

8

Which of the following events occurs during interphase of the \n cell cycle?

replication of the DNA

One difference between cancer cells and normal cells is that \n cancer cells ________.

continue to divide even when they are tightly packed \n together