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Biology 1 > Part of "At the molecular and cellular level" and Cell structure part 1 > Flashcards

Part of "At the molecular and cellular level" and Cell structure part 1 Flashcards

1
Q

What did James Watson and Francis Crick discover?

A

1953: Structure of DNA was Double Helix

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2
Q

What is X-Ray Chrystallography?

A

Method to determine structure of small molecules

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3
Q

What is the structure of DNA?

A

Sugar-phosphate backbone + nitrogenous base

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4
Q

What composes a nucleotide?

A

A nitrogenous base + sugar + phosphate

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5
Q

What sugar is in the DNA?

A

Deoxyribose

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6
Q

Where is the nitrogenous base attached to?

A

1’ (1st carbon of sugar)

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7
Q

What are the pairs of the nitrogenous pairs?

A

Adenine-Thymine

Cytosine-Guanine

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8
Q

What does antiparallel mean?

A

They go in the opposite direction
5’———————3’
3’———————5’

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9
Q

Where is the phosphate group attached?

A

On the 5’ (5th carbon on sugar)

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10
Q

What is the 3’?

A

the 3rd carbon on sugar which is free; meaning another nucleotide can be added

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11
Q

Find the complementary strand of this

5’-AGTCGTGACAGT-3’

A

3’-TCAGCACTGTCA-5’

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12
Q

What are pyrimidine?

What is their form?

A

Cytosine, Thymine (in DNA), and Uracil (in RNA)
They have one ring.
(small –> CUT the pie)

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13
Q

What are Purines?

What is their form?

A

Adenine and Guanine

They have two rings fused together

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14
Q

How many bonds does A form with T?

A

2 H bonds

2 hydrogen bonds

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15
Q

How many bonds dies G form with C?

A

3 H bonds

3 Hydrogen bonds

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16
Q

What structure does a Purine + Pyrimidine form?

A

A ladder structure

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17
Q

In what form does an RNA molecule exist?

A

As a single strand

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18
Q

What type of base pairings can occur with RNA molecules?

A
  • Between two different RNA molecules

- Within the same RNA molecule

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19
Q

What types of RNA molecules are there?

A
  • mRNA
  • tRNA
  • rRNA
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20
Q

How does DNA replication occur?

A

The RNA comes, breaks the bonds in the DNA, adds the complementary nucleotide to the template according to base pairing rules

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21
Q

What is the accuracy of the DNA reproduction?

A

very accurate

only one mistake per 10 billion nucleotides

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22
Q

What causes cancer?

A

The accumulation of mistakes- That’s why older people are more prone to cancer

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23
Q

Where does replication begin? How many do eukaryotic chromosomes have?

A

At an origin of replication that are recognized by proteins that attach to the DNA
Eukaryotic chromosomes have 100s-1000s that eventually fuse

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24
Q

What is a replication Bubble?

A

Where the DNA opens and the RNA goes in

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25
Q

What is the replication fork?

A

Y-shaped area where parental strands are being unwound

-Each bubble has two because the RNA copies the DNA template on both sides

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26
Q

What are DNA polymerases? What do they do?

A
  • They are enzymes

- They add nucleotides make complementary strands

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27
Q

How do you go to gene from protein?

A
  • The content of genes in specific nucleotide sequence in DNA leads to specific traits by directing synthesis of proteins (and RNA molecules used in protein synthesis)
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28
Q

Genotype

A
  • Genetic makeup of an organism

- The actual genes a person has

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29
Q

Phenotype

A
  • Observable physical and physiological traits of an organism, which are determined by its genetic makeup- Only see dominant allele (recessive is observable when homozygous recessive)
30
Q

Proteins

A

Link between genotype and phenotype

31
Q

Gene expression

A

Process by which DNA directs making proteins or just RNA

DNA –> RNA –> Protein

32
Q

Two main parts in gene expression

A
  1. Transcription

2. Translation

33
Q

Transcription

Summary

A
  • Synthesis of RNA using information in DNA
  • Both nucleic acids written in similar languages
  • DNA strands are templates for making another DNA strand during replication AND for making a complementary sequence of RNA
  • For protein-coding genes, RNA molecule is copy of gene’s protein-building instruction (mRNA)
34
Q

Translation

Summary

A
  • Synthesis of polypeptide using information in mRNA
  • Change in language from nucleotides of mRNA to amino acids for polypeptide
  • Translation occurs at ribosomes where amino acids are linked into polypeptide chains
35
Q

Do organisms without a nucleus (prokaryotes) go through transcription and translation?

A

YES

Transcription and translation occur in all organisms

In prokaryotes:
- Translation of mRNA can start while transcirption still happening

in Eukaryotes:
- Spatial separation prevents this (one is inside nucleus, the other is outside)

36
Q

How many different types of amino acids are there?

A

20 amino acids

1 nucleotide CANNOT translate to 1 amino acid, it’s a sequence of 3 nucleotide bases (codons) that translate into 1 amino acid

37
Q

Codons

A
  • Triplets of nucleotide bases
  • Instructions for polypeptide chain written in DNA in codons
  • 64 codons exist
38
Q

Complementary sequence

A

The sequence that would bind to the DNA

39
Q

Steps for transcription

A
  1. RNA polymerase separates DNA strands
  2. RNA polymerase joins RNA nucleotides complementary to DNA template strand (Assembles polynucleotides in 5’-3’ direction)
40
Q

Steps for translation

A
  1. Ribosome attaches to mRNA
  2. tRNA binds AUG on mRNA (tRNA has anticodon to AUG, so UAC)
  3. tRNA adds attached amino acid
  4. Process continues until stop codon is reached
41
Q

Anticodon

A

Base-pairs with complementary codon on mRNA

42
Q

Cell division functions

A

In multicellular eukaryotes allows to:

  • Grow and develop
  • Repair (Replace dying cells, bone marrow cells –> new blood cells)
43
Q

Characteristics of cells produced by cell division

A
  • Most cell divisions result in genetically identical daughter cells
  • Each daughter cell has an identical copy of DNA
  • Cell division ends with 2 daughter cells (exceot in meisos which is 4)
44
Q

Steps of cell division

A
  1. DNA is replicated
  2. 2 copies of DNA moved to opposite ends of cell
  3. Splits into daughter cells
45
Q

Steps of cell division

A
  1. DNA is replicated
  2. 2 copies of DNA moved to opposite ends of cell
  3. Splits into daughter cells
46
Q

Chromosomes

A
  • Found in DNA
  • Long, linear DNA with many proteins
  • Proteins maintain the structure of chromosome and control activity of genes
  • When cell is not dividing –> long and thin chromatin fibres
  • When DNA replication begins –> chromosomes condense, becomes short and thick
47
Q

DNA + proteins

A

Chromatin

48
Q

Somatic cells

A
  • All body cells except reproductive cells

- Humans have 46 chromosome in each somatic cell made up of 2 sets of 23 (one set inherited from each parent)

49
Q

Gametes

A
  • Reproductive cells

- 23 chromosomes

50
Q

Sister chromatids

A

Joined copies of original chromosomes

  • Each duplicated chromosome has two sister chromatids
  • Each sister chromatid has a centromere
51
Q

Centromere

A

Where sister chromatids are most closely attached

52
Q

Individual chromatids

A

Once sister chromatids separate, they are individual chromosomes

  • There is double the usual amount of chromosomes in the cell
53
Q

Mitosis

A
  • Nuclear division in eukaryotic cells

- Followed by cytokinesis

54
Q

Cytokinesis

A
  • Division of cytoplasm’

- One cell becomes two

55
Q

Mitochondria

A

Functions:

  • Transforms energy
  • Sites of cellular respiration
  • Use oxygen to make ATP from sugars, fats, and other fuels

Characteristics:

  • Occur in most eukaryotic cells
  • 2 membranes enclosing it (Each has a phospholipid bilayer with embedded proteins)
  • Outer membrane is smooth
  • Inner membrane is convoluted (has cristae)
  • Inner compartment between the 2 membranes (intermembrane space)
  • Compartment enclosed by inner membrane is mitochondrial matrix (contains enzymes, mtDNA, sibosomes)
56
Q

Chloroplasts

A

Functions:

  • Transform energy
  • Found in plants and algae
  • Sites of photosynthesis, solar energy converted to chemical energy
  • Functions in photosynthesis

Characteristics:

  • Found in leaves
  • Contain chlorophyll
  • Bounded by a double membrane (inner and outer membranes)
  • Intermembrane space
  • Presence of another membrane system inside (thyglakoids, granum, stroma)
57
Q

Thylakoids

A
  • Flattened

- Interconnected sacs

58
Q

Granum

A

Stack of thylakoids

59
Q

Stroma

A

the fluid outside of the thylakoids that contains chloroplast DNA, ribosomes, enzyme

60
Q

Endosymbiotic

A

A cell living within another cell

61
Q

Peroxisomes

A
  • Bounded by 1 membrane
  • Contain enzymes tht remove H atomes and transfer them to oxygen
  • Contain enzymes to convert peroxide to water

Functions:

  • Make hydrogen peroxide
  • Use oxygen to break down fatty acids
  • detoxify alcohol and poisons in the liver
62
Q

Cytoskeleton

A
  • Network of fibre extending throughout the cytoplasm

functions:

  • Keep cell shape
  • Make the cell move (cell motility; requires interaction with motor proteins)
  • Mechanical support for cell
  • Maintains cell shape (animal cells do not have cell walls)
  • Acts as an anchor for organelles and enzymes
  • Broken down and rebuilt in different parts of cell to change shape
  • Let the cell move along fibres outside of cekk
  • Inside: helps vesicles with neurotransmitters get to where they need to be released; helps plasma membrane bend to form food vacuoles (phagocytic vesicles)
63
Q

Types of cytoskeleton

A
  1. Microtubules (thickest)
  2. Microfilaments (Thinnest)
  3. Intermediate filaments
64
Q

Mircotubules

A
  • Hollow rods
  • Constructed from tubulin (Globular,beta and alpha tubulin)
  • Grow by adding tubulin
  • Arrangement of 2 subunits of tubulin
  • Plus side: the side that can grow and shrink faster than the other (plus end show rates of growth/shrinking are higher)
  • Responsible for beating of flagella and cilia
65
Q

Flagella

A
  • Long cellular appendage used for locomotion
  • Used to move through water
  • Present in sperms
  • Long and very few (1 or 2 per cell)
  • Undulates like the tail of a fish
  • Has a group of microtubules sheathed in extension of the plasma membrane
  • Has 9 doublet of microtubules placed in a ring formation with 2 microtubules in the center
  • Anchored in cell by a basal body
66
Q

Cilium

A
  • Short appendage specialized for locomotion or moving fluid past the cell
  • Used to move through water
  • Lines the trachea to move mucus and trapped debris out of lungs
  • Short and numerous
  • Cilia work like oars with power and recovery strokes (a paddling movement)
  • Can act like an antenna by receiving signals for the cell (only 1 per cell; is non-motile)
  • Has a group of microtubules sheathed in extension of plasma membrane
  • Has 9 doublets of microtubules arranged in a ring formation with 2 microtubules in the center called 9+2 pattern (non-motile cilia have 9+0 pattern)
  • Anchored in cell by a basal body
67
Q

Cilia vs flagella

A

Similar:

  • Used to move around in water
  • Have a group of microtubules sheathed in extension of plasma membrane
  • Have 9 doublets of microtubules arranged in a ring with 2 microtubules in centre of ring
  • Anchored in cell by a basal body

Differences:

  • Cilia is shorter and more numerou sthan flagella
  • Different movement (cillia –> paddle, while flagella –> undulates)
  • Present in different areas
68
Q

Basal body

A
  • Where the cilia and flagella attach to the cell

- Similar to centriole

69
Q

Microfilaments

A

Actin filaments

Characteristics:

  • Thin solid rods
  • Built from actin, a globular protein
  • Twisted double chain of actin subunits
  • Occur as linear filaments and structural networks (Protein can bind along side of filament and let another filament extend as a branch)
  • Bear tension, pulling forces
  • 3-D network inside plasma membrane helps support cell shape (cortical microfilaments)
  • Bundle of microfilaments make up core of microvilli
  • Used with protein myosin to move
70
Q

Cortical mircrofilaments

A
  • 3-D network just inside plasma membrane that helps support cell shape
  • Inside microfilaments
  • Gives cell cortex (outer cytoplasmic layer of cell) more gel consistency
  • Inside is more fluid
71
Q

Intermediate filaments

A
  • Only found in cells of animals
  • Bear tension
  • There are different types of intermediate filaments
  • More permanent than microtubules and microfilaments
  • Very sturdy

Functions:

  • Reinforce shape of cell
  • Fix position of certain organelles

Biology 1 (11 decks)

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