Chapter 3: Cells Flashcards

Question

Nucleus pores

Answer 1

extend through the nuclear envelope * Allow certain substances to move between the nucleus and the cytoplasm

Answer 2

present inside the nucleus * Sites of synthesis of rRNA and assembly of rRNA and proteins into ribosomal subunits

Answer 3

In cells that are not dividing, the DNA in the nucleus is associated with proteins to form a diff use mass of fi ne threads

Answer 4

cell division takes place, the DNA replicates (duplicates) and the loops condense even more to form short, thick structures

Answer 5

a single chromosome consists of a pair of identical strands, they are connected at a region called the centromere

Answer 6

o information encoded in a specific region of DNA is copied into a specific molecule of RNA o occurs in nucleus

Answer 7

- the RNA attaches to a ribosome, where the information contained in RNA is used to direct the assembly of amino acids into a protein - occurs in the cytoplasm

Answer 8

set of rules that relate the base triplet sequence of DNA to the corresponding codons of RNA and the amino acids they specify

Answer 9

Each DNA base triplet is transcribed into RNA as a complementary sequence of three nucleotides

Answer 10

1. Messenger RNA (mRNA) * Directs the synthesis of a protein 2. Ribosomal RNA (rRNA) * Joins with ribosomal proteins to make ribosomes 3. Transfer RNA (tRNA) * Binds to amino acid and holds it in place on a ribosome until it is incorporated into a protein during translation

Answer 11

UAA, UAG, UGA

Answer 12

Cell undergoes a nuclear division called mitosis and a cytoplasmic division called cytokinesis to produce two identical cells, each with the same number and kind of chromosomes as the original cell

Answer 13

o Mechanism that produces gametes, cells needed to form the next generation of sexually producing organisms o Meiosis: number of chromosomes is reduced by half , and cytokinesis

Answer 14

orderly sequence of events by which a somatic cell duplicates its contents and divides in two 1. Interphase phase (when cell is not dividing) 2. Mitotic phase (when cell is dividing)

Answer 15

o Interval between the mitotic phase and S phase o Cell is metabolically active o Organelles and cytoplasmic components replicate, but DNA does not. o Duration: 8–10 hours (varies in different cell types).

Answer 16

o DNA is copied, so each new cells will have an identical set of genetic material o Each DNA strand uncoils, and new bases pair with the old ones to create two identical DNA molecule o Duration: about 8 hours

Answer 17

o Cell grows more and prepares for division o Enzymes and proteins needed for cell division are produced o Centrosome replication is completed o Duration: 4-6 hours

Answer 18

MITOTIC PHASE

Answer 19

o DNA condenses into visible chromosomes o Each chromosome has 2 identical sister chromatid o Mitotic spindle forms and moves to opposite poles o Nuclear envelope disappears

Answer 20

o Chromosomes line up in the middle of the cell o Middle area is called: metaphase plate

Answer 21

o Centromeres split, and sister chromatids separate o Chromatids move to opposite poles, pulled by the mitotic spindle o Chromosomes look V-shaped as they are dragged

Answer 22

o Chromosomes uncoil back into chromatin (thread like form) o Nuclear envelope reforms around each set of DNA o Nucleolus reapers, and the spindle disappears

Answer 23

P = Prepare (DNA condenses, spindle forms) M = Middle (Chromosomes line up) A = Apart (Sister chromatids separate) T = Two nuclei form

Answer 24

is the final step of cell division, where the cytoplasm of a single cell splits into two separate daughter cells

Answer 25

1. Remain alive and functioning without dividing 2. To grow and divide 3. To die

Answer 26

transfer a phosphate group from ATP to a protein to activate the protein; other enzymes can remove the phosphate group from the protein to deactivate it

Answer 27

an orderly, genetically programmed death. a triggering agent from either outside or inside the cell causes “cell-suicide” genes to produce enzymes that damage the cell in several ways, including disruption of its cytoskeleton and nucleus. NORMAL

Answer 28

is a pathological type of cell death that results from tissue injury

Answer 29

increases surface area – common in epithelial cells that line the small intensities, where the large surface area speeds the absorption of digested food

Answer 30

o Vary in size o Shapes: round, oval, flat, cube shaped, column shaped, elongated, star shaped, disc shaped - Related to its function in the body

Answer 31

* Covers body surfaces, lines hollow organs and ducts and forms glands * Consist of closely packed cells with little extracellular material between them

Answer 32

1) Covering and lining epithelium o Forms the outer covering of the skin and some internal organs o Lines the lumen (interior space) of hollow structures such as blood vessels, ducts and organs 2) Glandular epithelium o Makes up the secreting portion of glands

Answer 33

enter the interstitial fluid and then diffuse directly into the bloodstream without flowing through a duct - sweat, oil, saliva, milk, digestive enzymes

Answer 34

regulate many metabolic and physiological activities to maintain homeostasis

Answer 35

1) Physical barrier that protects against harmful agents in the environment 2) Secretes substances onto the body surface or into hollow organs or blood 3) Absorbs material into the bloodstream or lymph

Answer 36

Functions: 1) Binds together, supports, strengthens other body tissues 2) Protects and insulates internal organs 3) Major transport system within the body 4) Primary location of stored energy 5) Main source of immune responses two basic elements - extracellular matrix - cells

Answer 37

1. Collagen fibers o Very strong and resist pulling forces o Chemically, they consist of the protein collagen 2. Elastic fibers o Smaller in diameter o Consists of molecules of a protein called elastin surrounded by a glycoprotein o Have elasticity property 3. Reticular fibers o Consisting of collagen and a coating of glycoprotein o Provide support and strength

Answer 38

material between the cells and the fibers of connective tissue (can be fluid, gel or solid) * Supports cells, binds them together, stores water

Answer 39

present in several connective tissues and usually are the most numerous. They migrate through the connective tissue, secreting the fibers and ground substance of the extracellular matrix.

Answer 40

develop from monocytes, a type of leukocyte. They are capable of engulfing bacteria and cellular debris by phagocytosis, a form of endocytosis

Answer 41

small cells that develop from a type of leukocyte called a B lymphocyte. Plasma cells secrete antibodies, proteins that attack or neutralize foreign substances in the body. Thus, plasma cells are an important part of the body’s immune response.

Answer 42

abundant alongside blood vessels that supply connective tissue. They produce histamine, a chemical that dilates blood vessels as part of the inflammatory response, the body’s reaction to injury or infection.

Answer 43

also called fat cells or adipose cells, are connective tissue cells that store triglycerides ( fats). They are found below the skin and around organs such as the heart and kidneys.

Answer 44

* Elongated cells called muscle fibers that are highly specialized to contract * Classified into three types: 1) Skeletal muscle o is usually attached to bones of the skeleton and is responsible for producing movement, maintaining posture, and generating heat. 2) Cardiac muscle o forms the bulk of the heart wall; its rhythmic contractions pump blood to all parts of the body 3) Smooth muscle o located in the walls of hollow internal structures such as blood vessels, airways to the lungs, the stomach, intestines, and urinary bladder

Answer 45

1) Cell body : contains nucleus and other organelles 2) Dendrites: major receiving or input portion of a neuron 3) Axon: output portion of a neuron, conducting action potentials toward another neuron

Answer 46

- Seals gaps between cells, preventing leakage. - Found in: Stomach, intestines, urinary bladder. - Prevents harmful substances from passing between cells into the blood

Answer 47

- Helps hold cells together with "adhesion belts". - Provides flexibility and resistance to separation. - Found in: Intestinal lining, epithelial cells

Answer 48

- What it does: Works like “spot welds” to keep cells strong. - Where it's found: Skin, heart muscles

Answer 49

- What it does: Attaches cells to a base layer (not to each other). - Where it's found: Skin, basement membranes.

Answer 50

- What it does: Creates small tunnels to share signals and nutrients. - Where it's found: Heart, nerves, bones