Chapter 4 Lecture - Genetics of Cellular Function Flashcards

(74 cards)

1
Q

Give 4 examples of genetic disorders that can impact hereditary traits.

A

Color blindness, cystic fibrosis, diabetes mellitus, and hemophilia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Define DNA

A

A long, thread-like molecule with uniform diameter, but varied length

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

There are ___ DNA molecules (chromosomes) in nucleus of most human cells

A

46

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

DNA and other nucleic acids are polymers of ______

A

nucleotides

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Nucleotides consist of what 3 things?

A

A sugar, phosphate group, and nitrogenous base

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Give an example of a type of sugar that can be found in nucleotides

A

Deoxyribose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are the two types of nitrogenous bases in nucleic acids?

A

1) Purines

2) Pyrimidines

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What distinguishes purines and pyrimidines from each other?

A

Purines have a double ring, pyrimidines have a single ring

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Which bases are purines and which bases are pyrimidines?

A

1) Purines - adenine (A) and guanine (G)

2) Pyrimidines - cytosine (C), thymine (T), and uracil (U)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are the 4 bases found in DNA? What are the 4 bases found in RNA?

A

DNA bases: A, T, C, G

RNA bases: A, U, C, G

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

DNA has a ______ _____ shape.

A

double helix

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

The nitrogenous bases of DNA are united by ______ bonds

A

hydrogen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

True or false: A purine on one strand always bound to a pyrimidine on the other

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

In DNA, the base A always pairs with ___ and G always pairs with ___

A

A - T & G - C

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

A–T has ___ hydrogen bonds

C–G has ___ hydrogen bonds

A

A–T has two hydrogen bonds

C–G has three hydrogen bonds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is the law of complementary base pairing?

A

The idea that one strand determines base sequence of other

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Define chromatin

A

Fine filamentous DNA material complexed with proteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Define a gene using two different definitions

A

1) A segment of DNA coding for the synthesis of a specific protein.
2) An information-containing segment of DNA that codes for synthesizing one or more proteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Define genome

A

All the genes of one person

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Humans have about _____ genes

A

20,000

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Genes only make up ____% of total DNA, the rest is noncoding DNA.

A

2%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

___ interprets the code in ___ to synthesize proteins

A

RNA interprets the code in DNA to synthesize proteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

RNA functions mainly in the _____

A

cytoplasm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What are the 3 important types of RNA for protein synthesis?

A
  • Messenger RNA (mRNA)
  • Ribosomal RNA (rRNA)
  • Transfer RNA (tRNA)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
In what 4 ways does RNA differ from DNA?
1) Single stranded (one nucleotide chain not a double helix like DNA) 2) Ribose replaces deoxyribose as the sugar 3) Uracil replaces thymine as a nitrogenous base 4) Functions mainly in cytoplasm
26
What determines the amino acid sequence of a protein?
The nucleotide sequence in the DNA
27
The minimum code to symbolize 20 amino acids is ____ nucleotides per amino acid
three
28
The body can make millions of different proteins based on only ___ amino acids and is encoded by genes made of just ___ nucleotides
The body can make millions of different proteins based on only 20 amino acids and is encoded by genes made of just four nucleotides
29
Define a base triplet
A sequence of three DNA nucleotides that stands for one amino acid
30
Define a codon
The 3-base sequence in mRNA
31
How many codons are there?
64 possible codons available to represent the 20 amino acids.
32
__ codons code for amino acids; __ are stop codons
61 codons code for amino acids; 3 are stop codons
33
What are stop codons?
They signal “end of message”
34
What are start codons?
AUG codes for methionine, and begins the amino acid sequence of the protein
35
Define transcription
Copying genetic instructions from DNA to mRNA
36
Define RNA polymerase
An enzyme that binds to DNA and assembles mRNA
37
How does RNA polymerase assemble mRNA?
1) RNA polymerase reads bases from one strand of DNA | 2) Makes corresponding mRNA
38
What is translation?
The process that converts the language of nucleotides into the language of amino acids
39
What 3 things participate in the process of translation?
mRNA, tRNA, and ribosomes
40
Briefly describe the process of translation
1) mRNA carries code from nucleus to cytoplasm 2) Transfer RNA (tRNA) delivers a single amino acid to the ribosome for it to be added to growing protein chain 3) Ribosome adds the amino acid to the protein chain.
41
_RNA contains an anticodon that are complementary to codon of mRNA
tRNA
42
Where are ribosomes found and what are they made of?
1) Found free in cytosol, on rough ER, and on nuclear envelope 2) Consist of enzymes and ribosomal RNA (rRNA)
43
Describe the structure of tRNA
1) One end includes three nucleotides called an anticodon | 2) Other end has binding site specific for one amino acid
44
What are the 3 steps to translation?
Initiation, Elongation, and Termination
45
Describe the step of initiation (3 parts)
1) Initiator tRNA (bearing methionine) pairs with start codon 2) Ribosome pulls mRNA molecule through it like a ribbon 3) When start codon (AUG) is reached, protein synthesis begins
46
Describe the step of elongation (6 parts)
1) Next tRNA (with its amino acid) binds to ribosome while its anticodon pairs with next codon of mRNA 2) Peptide bond forms between methionine and second amino acid 3) Ribosome slides to read next codon 4) Next tRNA with appropriate anticodon brings its amino acid to ribosome 5) Another peptide bond forms (between 2nd and 3rd amino acids) 6) Process continually repeats, extending peptide to a protein
47
Describe the step of termination (3 steps)
1) Ribosome reaches stop codon 2) Finished protein breaks away from ribosome 3) Ribosome dissociates into two subunits
48
Describe DNA replication (4 steps)
1) DNA unwinds from histones 2) An enzyme unzips a segment of the double helix exposing its nitrogenous bases 3) DNA polymerase builds new DNA strands 4) Newly made DNA wraps around histones
49
Before a cell divides, it must duplicate its DNA. Why?
So it can give a complete copy of all its genes to each daughter cell
50
When preparing to divide, the cell makes copy of ____ DNA
nuclear
51
When preparing to divide, after nucelar DNA is replicated, each chromosome then consists of two parallel filaments of identical DNA called ______
Sister chromatids
52
Where are chromatids joined?
At the centromere
53
Define cell cycle
A cell’s life from one division to the next
54
What are the two main parts of the cell life cycle?
Interphase and mitotic phase
55
What does interphase of the cell cycle include
1) G1: first gap phase 2) S: synthesis phase 3) G2: second gap phase
56
What does the mitotic phase of the cell cycle include?
Prophase, Metaphase, Anaphase, Telophase
57
Describe G1 of interphase
- The first gap phase; the interval between cell birth (from division) and DNA replication - Cell carries out normal tasks and accumulates materials for next phase
58
Describe the S stage of interphase
Synthesis phase; the cell replicates all nuclear DNA and duplicates centrioles
59
Describe G2 of interphase
- The second gap phase; the interval between DNA replication and cell division - Cell repairs DNA replication errors, grows and synthesizes enzymes that control cell division
60
Briefly describe the mitotic phase of cell division
The cell replicates its nucleus and pinches in two to form new daughter cells
61
What is the G0 phase?
Describes cells that have left the cycle and cease dividing for a long time (or permanently)
62
True or false: Cell cycle duration varies between cell types
True
63
Define mitosis
Mitosis is cell division resulting in two genetically identical daughter cells
64
What are the 4 main functions of mitosis?
1) Development of the individual from one fertilized egg to roughly 50 trillion cells 2) Growth of all tissues and organs after birth 3) Replacement of cells that die 4) Repair of damaged tissues
65
What are the 4 stages of mitosis/ the mitotic phase?
Prophase, metaphase, anaphase, telophase
66
Describe the prophase stage of mitosis (6 steps)
1) Genetic material condenses into compact chromosomes 2) 46 chromosomes are made of two sister chromatids 3) Nuclear envelope disintegrates 4) Centrioles sprout spindle fibers (long microtubules) 5) Spindle fibers push centriole pairs apart 6) Some spindle fibers attach to kinetochores of centromeres of chromosomes
67
Describe the metaphase stage of mitosis (2 steps)
- Chromosomes are aligned on cell equator | - Shorter microtubules from centrioles complete an aster which anchors itself to inside of cell membrane
68
Describe the anaphase stage of mitosis (2 steps)
- Enzyme cleaves two sister chromatids apart at centromere - Single-stranded daughter chromosomes migrate to each pole of the cell as motor proteins in kinetochores crawl along spindle fibers
69
Describe the telophase stage of mitosis (5 steps)
- Chromosomes cluster on each side of the cell - Rough ER makes new nuclear envelope around each cluster - Chromosomes uncoil to chromatin - Mitotic spindle disintegrates - Each nucleus forms nucleoli
70
Define cytokinesis
The division of cytoplasm into two cells
71
True or false: Telophase is the end of nuclear division but overlaps cytokinesis
True
72
Describe the stage of cytokinesis (2 steps)
1) Creates cleavage furrow around the equator of cell | 2) Cell eventually pinches in two
73
Cells replicate under what conditions?
Cells replicate if: - They have enough cytoplasm for two daughter cells - They have replicated their DNA - They have adequate supply of nutrients - They are stimulated by growth factors (chemical signals) - Neighboring cells die, opening up space
74
Cells stop dividing under what conditions?
1) They snugly contact neighboring cells 2) Nutrients or growth factors are withdrawn 3) They undergo contact inhibition—the cessation of cell division in response to contact with other cells