Chapter 5 - The Nucleus, DNA Expression, And The Cell Cycle

Question 1

Uninucleate

Answer 1

Cell with only one nucleus

Question 2

Multinucleate

Answer 2

Cell with more than one nucleus

Question 3

Anucleate

Answer 3

Cell without nucleus

Question 4

Nuclear envelope

Answer 4

Encloses the nucleus & consists of an outer & inner membrane

Question 5

Nuclear pores

Answer 5

Large, circular openings where the inner & outer membranes fuse & allow the nucleus to exchange materials with the cytosol

Question 6

Nucleoplasm

Answer 6

Fluid inside nucleus; major organic components: DNA, RNA, ribosomal proteins, enzymes, & nucleotides

Question 7

Nucleolus

Answer 7

Dark-staining region inside nucleoplasm where RNA molecules & proteins come together to form large or small ribosomal subunits

Question 8

Chromatin

Answer 8

Structural material that comprises a chromosome

Question 9

Histones

Answer 9

Group of globular proteins

Question 10

Nucleosome

Answer 10

The “bead” within an entire DNA-histone complex resembles a beaded necklace

Question 11

Haploid number (n)

Answer 11

Number of chromosomes in the nucleus of a human gamete (sex cell = egg/sperm) - 23

Question 12

Sex chromosome

Answer 12

One of 23 different chromosomes that plays a role in determining the sex of the person

Question 13

Autosomes

Answer 13

Other 22 chromosomes in the gamete

Question 14

Diploid number (2n)

Answer 14

46 = 23 chromosomes existing in pairs; number of chromosomes in nucleus of a typical body cell

Question 15

Genes

Answer 15

Functional segments within nucleus of DNA molecules that provide a chemical code specifying number, type, & arrangement of amino acids in proteins

Question 16

One gene-one polypeptide theory

Answer 16

Theory that genes contain chemical instructions necessary to synthesize polypeptides

Question 17

Genome

Answer 17

All genes on all different types of chromosomes in your cells

Question 18

Central dogma of molecular biology

Answer 18

Phenomenon whereby genetic information passes from a DNA molecule to an RNA molecule and ultimately to protein

Question 19

2 major processes of central dogma

Answer 19

Transcription & translation

Question 20

Transcription (RNA synthesis)

Answer 20

Represents the first step in the central dogma whereby genetic information passes from one type of nucleic acid to another type

Question 21

DNA template

Answer 21

Contains base sequence used to direct synthesis of an RNA molecule

Question 22

Types of RNA

Answer 22

Ribosomal RNA
Messenger RNA
Transfer RNA

Question 23

Ribosomal RNA (rRNA)

Answer 23

Helps structurally reinforce a ribosome & may play a role in linking amino acids together during protein synthesis

Question 24

Messenger RNA (mRNA)

Answer 24

Carries copy of DNA’s genetic message for protein synthesis from the nucleus to a ribosome

Question 25

Transfer RNA (tRNA)

Answer 25

Brings amino acids to a ribosome so they can come together to form a protein

Question 26

Anticodon

Answer 26

One end of tRNA that displays three nitrogenous bases

Question 27

Translation

Answer 27

Process by which a cell uses the sequence of codons on an mRNA molecule to determine the sequence of particular amino acids in a protein

Question 28

5 major steps of translation

Answer 28

1. Binding mRNA with small ribosomal subunit 2. Formation of ribosome & entry of next tRNA 3. Formation of a peptide bond 4. Translocation 5. The stop codon ends translation

Question 29

Polyribosome

Answer 29

Two or more ribosomes translating the same mRNA at the same time

Question 30

Leader sequence

Answer 30

First few amino acids to become part of the growing polypeptide after completion of of translation occurs at the rough ER

Question 31

Cellular differentiation

Answer 31

Process by which similar cells become different from one another through the expression of different genes