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hellp Flashcards

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1
Q

What are the macromolecules that make up our genetic material?

A

Nucleic acids

Nucleic acids contain instructions for making proteins.

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2
Q

What do proteins carry out?

A

ALL cellular activity

Proteins are essential for various functions within cells.

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3
Q

Name the two types of nucleic acids.

A
  • DNA: Deoxyribonucleic acid
  • RNA: Ribonucleic acid

These nucleic acids are crucial for genetic information storage and transfer.

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4
Q

What are nucleotides?

A

The building blocks (monomers) of DNA and RNA (polymers)

Nucleotides link together to form nucleic acids.

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5
Q

List the three parts of a nucleotide.

A
  • Phosphate group: PO4
  • Pentose (5-C) sugar: deoxyribose or ribose
  • Nitrogenous Base: carbon ring structure that contains 1 or more nitrogen atoms

Each part plays a critical role in the structure and function of nucleotides.

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6
Q

What are the two types of nucleotides based on their nitrogen bases?

A
  • Purines: double ring N base
  • Pyrimidines: single ring N base

Purines include Adenine (A) and Guanine (G), while Pyrimidines include Cytosine (C), Uracil (U), and Thymine (T).

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7
Q

Name the purines.

A
  • Adenine (A)
  • Guanine (G)

Purines are characterized by their double ring nitrogen base structure.

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8
Q

Name the pyrimidines.

A
  • Cytosine (C)
  • Uracil (U) Only in RNA
  • Thymine (T) Only in DNA

Pyrimidines have a single ring nitrogen base structure.

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9
Q

What is the structure of DNA described as?

A

Double helix (“twisted ladder”)

This structure is characterized by two strands that twist around each other.

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10
Q

Define antiparallel in the context of DNA.

A

Two complementary strands run in opposite directions

This orientation is crucial for the replication and function of DNA.

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11
Q

What forms the sugar-phosphate backbone of DNA?

A

Sugars and phosphates

This backbone provides structural support for the DNA molecule.

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12
Q

How are sugars and phosphates bonded in DNA?

A

Through phosphodiester bonds

These bonds link the sugar of one nucleotide to the phosphate of the next.

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13
Q

What branches off the sugar-phosphate backbone?

A

Nitrogenous bases

These bases are essential for encoding genetic information.

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14
Q

How are bases bonded in DNA?

A

Through hydrogen bonds

These bonds are weaker than covalent bonds, allowing for the separation of strands during replication.

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15
Q

In DNA, which bases pair together?

A
  • A to T (using 2 hydrogen bonds)
  • G to C (using 3 hydrogen bonds)

This specific pairing is critical for the structure and function of DNA.

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16
Q

What does Chargaff’s Rule state?

A
  • %A = %T in a DNA strand
  • %G = %C in a DNA strand

This rule reflects the base pairing in the DNA structure.

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17
Q

What does RNA stand for?

A

RiboNucleic Acid

RNA plays a crucial role in the synthesis of proteins based on the instructions from DNA.

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18
Q

What is the purpose of RNA?

A

To carry out the instructions coded in DNA

RNA acts as a messenger between DNA and the ribosomes where proteins are synthesized.

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19
Q

What sugar is found in RNA instead of deoxyribose?

A

Ribose

This difference is one of the key distinctions between DNA and RNA.

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20
Q

How does the structure of RNA differ from DNA?

A

Single stranded instead of double helix

This structural difference allows RNA to perform various functions in the cell.

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21
Q

In RNA, which base pairs with Adenine?

A

Uracil (NO thymine)

This substitution is a key difference between RNA and DNA.

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22
Q

What are chromosomes?

A

Long, tightly coiled (condensed) strands of DNA

Chromosomes are visible during cell division and contain genetic information.

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23
Q

Do more chromosomes indicate a more complex organism?

A

No

Different organisms have different numbers of chromosomes, but complexity is not solely determined by chromosome number.

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24
Q

What is a gene?

A

A piece/section of DNA that has instructions to code for a protein

Genes are the fundamental units of heredity and function.

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25
Eukaryotes usually have more than one __________.
chromosome ## Footnote Eukaryotic cells typically contain multiple chromosomes, unlike prokaryotes which usually have a single circular chromosome.
26
Each **chromosome** can have over __________ base pairs.
100,000,000 ## Footnote This large number of base pairs allows for the coding of several thousand genes.
27
Each chromosome is really one long piece of linear DNA folded with lots of __________ attached.
proteins ## Footnote The folding and packaging of DNA with proteins help in the organization and regulation of gene expression.
28
Chromosomes have many origins of __________.
replication ## Footnote Multiple origins of replication allow for efficient DNA synthesis during cell division.
29
Each chromosome has one short arm (__) and one long arm (__).
p, q ## Footnote The short arm is designated as 'p' and the long arm as 'q'.
30
The **centromere** is a section of repeating sequences near the __________.
center ## Footnote The centromere is crucial for the attachment of spindle fibers during cell division.
31
What are **telomeres**?
Repeating sequences on the ends of chromosomes ## Footnote Telomeres protect genetic information during cell division and shorten with each division until the cell can no longer divide.
32
Each time a cell divides, telomeres become __________.
shorter ## Footnote This shortening process is linked to cellular aging and limits the number of times a cell can divide.
33
DNA strands run from the **5’ to 3’ direction**. What does this indicate?
The directionality of DNA strands ## Footnote This indicates the orientation of the sugar-phosphate backbone in DNA.
34
What does **antiparallel** mean in the context of DNA strands?
Two complementary strands run in opposite directions ## Footnote One strand is 5’ → 3’ and the other is 3’ → 5’.
35
In DNA, which end begins with **PO4**?
5’ end ## Footnote This end is considered 'right-side up'.
36
In DNA, which end begins with **OH**?
3’ end ## Footnote This end is considered 'upside down'.
37
How are the **carbons in the sugar** labeled in DNA?
From 1’ to 5’ ## Footnote This labeling helps identify the specific carbons in the sugar molecule.
38
What type of bonds join the **3’ carbon** of the first nucleotide to the **5’ carbon** of the second nucleotide?
Phosphodiester bonds ## Footnote These bonds form the backbone of the DNA strand.
39
DNA has a **5’ end** and a **3’ end**. What is the significance of these ends?
They indicate the directionality of the DNA strand ## Footnote This directionality is crucial for processes like replication and transcription.
40
When do we need to make new body/somatic cells?
During **mitosis** ## Footnote Mitosis is the process of cell division for growth and repair.
41
When do we need to make new sex cells/gametes?
During **meiosis** ## Footnote Meiosis is the process of cell division that produces sperm and egg cells.
42
When DNA is replicated, what happens to the original chromosome and its new copy?
They stay attached at the **centromere** ## Footnote This attachment is crucial for proper segregation during cell division.
43
What are **sister chromatids**?
Two identical copies of one chromosome attached at the centromere ## Footnote Sister chromatids will be separated later during cell division.
44
What type of replication is DNA replication?
semi-conservative ## Footnote Each new DNA strand consists of one original and one new strand.
45
What is the role of **DNA helicase** in DNA replication?
unwinds (“unzips”) the DNA helix ## Footnote This enzyme is crucial for separating the two strands of DNA.
46
What are the **daughter strands** in DNA replication?
new strands of DNA ## Footnote They are formed alongside the original parent strands.
47
What does **DNA polymerase** do during replication?
adds new complementary nucleotides in the 5’ to 3’ direction ## Footnote This enzyme is essential for building the new DNA strands.
48
What is a **replication fork**?
where DNA is being unwound to create a 'replication bubble' ## Footnote It is the area where the two strands of DNA separate.
49
What is the function of **single-strand binding proteins (SSBPs)**?
keep the DNA strands separated & stable ## Footnote They prevent the strands from re-annealing during replication.
50
What does **topoisomerase** do during DNA replication?
prevents DNA strands from over-winding ## Footnote This enzyme helps manage the tension in the DNA as it unwinds.
51
What is the purpose of **primase** in DNA replication?
lays down RNA primers for DNA polymerase III ## Footnote Primers are necessary for initiating the synthesis of new DNA strands.
52
What energy source is used when new nucleotides are added to the DNA strand?
3 phosphate groups ## Footnote The breaking of these groups provides the energy needed for bond formation.
53
True or false: DNA replication starts at a single end of the DNA strand.
FALSE ## Footnote Replication occurs at multiple sites, forming replication bubbles.
54
How many **base pairs** do E. coli bacteria copy in their single chromosome in less than 1 hour?
5 million ## Footnote This rapid replication is a characteristic of prokaryotic cells.
55
How many **bases** do human cells copy when dividing into daughter cells?
6 billion ## Footnote Human cells complete this process in only a few hours.
56
What is the average number of **errors** per cell cycle during DNA replication?
~30 errors ## Footnote This translates to about 1 error per 100 million base pairs.
57
According to **cell theory**, where do all cells come from?
Pre-existing cells ## Footnote This principle underlines the process of cell division.
58
What are the **reasons for cell division**?
* Growth * Repair/renewal * Asexual reproduction in unicellular organisms ## Footnote These reasons highlight the importance of cell division in organisms.
59
What are **somatic cells**?
All the cells in your body that are NOT sex/reproductive cells ## Footnote Somatic cells have a diploid number of chromosomes.
60
What are **gametes**?
Eggs and sperm ## Footnote Gametes are the sex/reproductive cells.
61
How many chromosomes do **somatic cells** have in humans?
46 ## Footnote Somatic cells are diploid (2n), meaning they have two copies of each chromosome.
62
How many chromosomes do **gametes** have in humans?
23 ## Footnote Gametes are haploid (n), meaning they have one copy of each chromosome.
63
During **meiosis**, what happens to the copies of chromosomes?
Copies are sorted and separated ## Footnote This process is crucial for the formation of gametes.
64
What is produced during **mitosis**?
Identical copy of genetic material (DNA) ## Footnote Mitosis ensures that each daughter cell receives an identical set of chromosomes.
65
What is produced during **cytokinesis**?
Organelles, cytoplasm, cell membrane, and enzymes ## Footnote Cytokinesis occurs after mitosis.
66
What is the **cell cycle**?
Sequence of growth and division of a cell ## Footnote Parent cells (diploid) divide into two identical daughter cells (diploid).
67
What are the two main stages of the **cell cycle**?
* Interphase * Mitosis ## Footnote These stages encompass the growth and division processes of the cell.
68
What occurs during **interphase**?
* Regular cell activities * Preparation for division ## Footnote Interphase is the longest phase of the cell cycle.
69
What happens during the **G1 phase** of interphase?
Growth 1 ## Footnote The cell grows and performs everyday functions.
70
What occurs during the **S phase** of interphase?
DNA Synthesis ## Footnote Chromosomes are copied (DNA replication) during this phase.
71
What happens during the **G2 phase** of interphase?
Growth 2 ## Footnote Cells prepare for division and grow more, duplicating organelles, proteins, and membranes.
72
What is the state of DNA during interphase?
Loosely packed into long chromatin fibers ## Footnote This allows for easier access during DNA replication.
73
What appears during interphase as the cell prepares for mitosis?
Centrosomes ## Footnote Centrosomes play a key role in organizing the mitotic spindle.
74
Why are two copies of DNA needed during cell division?
To make two identical daughter cells ## Footnote Correct separation of these copies is crucial for genetic stability.
75
**Centrioles** are paired organelles found in which type of cells?
Animal cells ## Footnote Centrioles organize microtubules (spindle fibers) and help guide chromosomes during mitosis.
76
What do **homologous chromosomes** carry?
* Same size * Same genes (with variations) ## Footnote One chromosome from each parent makes the cell diploid.
77
What is a **duplicated chromosome** also known as?
X-shaped chromosome ## Footnote It consists of 2 sister chromatids containing the exact same genetic information.
78
What is the process of **mitosis**?
Dividing cell DNA to create two identical daughter cells ## Footnote Mitosis consists of 4 phases: Prophase, Metaphase, Anaphase, Telophase (PMAT).
79
What happens during **Prophase**?
* Chromatin condenses into visible chromosomes * Centrioles move to opposite poles of the cell * Nucleolus disappears * Nuclear membrane breaks down ## Footnote Protein fibers cross the cell to form the mitotic spindle.
80
What are **kinetochores**?
* Protein structures that help spindle fibers attach to centromeres * Connect centromeres to centrioles ## Footnote Microtubules attach to kinetochores, helping chromosomes move.
81
During **Metaphase**, where do chromosomes align?
Along the middle of the cell (metaphase plate) ## Footnote Spindle fibers coordinate movement to help chromosomes separate properly.
82
What happens to sister chromatids during **Anaphase**?
* Proteins holding sister chromatids together are inactivated * Sister chromatids separate at kinetochores * Move apart to opposite poles ## Footnote They become individual chromosomes after separating.
83
What forms during **Telophase**?
* Two daughter nuclei * Nuclear membranes & nucleoli reform * Chromosomes relax into chromatin ## Footnote Chromosomes are no longer visible under a light microscope.
84
What is **cytokinesis**?
Physically dividing the cytoplasm to form two separate cells ## Footnote A cleavage furrow forms in animal cells, while a cell plate forms in plant cells.
85
What are the **three major checkpoints** in the cell cycle?
* G1 * G2 * M ## Footnote These checkpoints ensure that cell division occurs correctly.
86
What is **density-dependent inhibition**?
Cells continue dividing until they run out of room ## Footnote It is an external signal that regulates cell division.
87
What is the role of **growth factors**?
Proteins that stimulate cell division ## Footnote They serve as external signals in the cell cycle.
88
What is the difference in **cytokinesis** between animal and plant cells?
* Animal cells: cleavage furrow forms * Plant cells: cell plate forms ## Footnote In plants, vesicles line up at the equator and fuse to form new cell membranes.
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