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HESI > Biology basics > Flashcards

Biology basics Flashcards

1
Q

What is the order for the hierarchic organizational system for nomenclature?

A 
Kingdom
Phylum
Class
Order
Family
Genus
Species
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2
Q

What are the steps in the scientific method?

A

observation- New observations are made and/or previous data are studied.

hypothesis- a statement or explanation of certain events or happenings.

experiment- a repeatable procedure of gathering data to support or refute the hypothesis.

conclusion- the data and its significance are fully explained.

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3
Q

What is specific heat?

A

The amount of heat necessary to raise the temperature of 1 gram of that molecule by 1° Celsius.

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4
Q

What are the most important molecules in biology?

A

carbohydrates, lipids, protein, nucleic acids

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5
Q

What are carbohydrates?

A

long chains, or polymers, of sugars

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6
Q

What are the main functions of carbohydrates?

A

storage, structure, energy, and form the backbone of important molecules such as DNA and RNA.

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7
Q

What are lipids?

A

fats, but specifically they are fatty acids, phospholipids, and steroids

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8
Q

What are saturated fats?

A

A category of fatty acid.
Contain no double bonds in their hydrocarbon tail.
Solid

the general public considers detrimental; cardiovascular problems are likely associated with diets containing high quantities of saturated fats.

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9
Q

What is unsaturated fat?

A

One of the two categories of fatty acids.
Liquid at room temperature
one or more double bonds.
hydrocarbon tail of the fatty acids is nonpolar and nonsoluble in water

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10
Q

What is a phospholipid?

A

Phospholipids consist of two fatty acids of varying length bonded to a phosphate group.

The phosphate group is charged and, therefore, polar and soluble in water

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11
Q

What are steroids?

A

The last of the lipids.
They are a component of membranes.
Many are precursors to significant hormones and drugs.

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12
Q

What is the most significant contributor to cellular function?

A

Proteins

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13
Q

What are proteins?

A

They are polymers of 20 molecules called amino acids.

Proteins are complex, consist of several structure types, and are the largest of the biologic molecules.

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14
Q

What are enzymes?

A

Particular types of proteins that act to catalyze different reactions or processes.
Nearly all cellular function is catalyzed by some type of enzyme.

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15
Q

What are amino acids?

A

Organic compounds that contain at least one amino group and a carboxyl group; building blocks of proteins.

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16
Q

What are nucleic acids?

A

components of the molecules of inheritance (i.e. DNA, RNA).

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17
Q

What is DNA?

A
  • DNA is a unique molecule specific to a particular organism;
  • it contains the genetic code that is necessary for replication.
  • the genetic material of a cell and is the vehicle of inheritance
  • double helix showing the general structure of a nucleotide and the two kinds of “base pairs”: adenine (A) with thymine (T) and guanine (G) with cytosine (C)
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18
Q

What is RNA?

A
  • Used in transfer of information from DNA to protein level and as a messenger in most species of the genetic code.
  • Nucleic acid found in both the nucleus and cytoplasm of the cell;
  • occurs in three forms: mRNA, ribosomal RNA, and tRNA.
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19
Q

What is metabolism?

A

the sum of all chemical reactions that occur in an organism

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20
Q

What is metabolic pathways?

A
  • Series of linked chemical reactions.
  • progressing from a standpoint of high energy to low energy.
  • All of the reactions are catalyzed by the use of enzymes.
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21
Q

What is a cell?

A
  • the fundamental unit of biology.
  • two types of cells: prokaryotic and eukaryotic cells.
  • consist of many components, most of which are referred to as organelles.
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22
Q

What are organelles?

A

Any of many cell “organs” or organized components.

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23
Q

What are Prokaryotic cells?

A
  • lack a defined nucleus

- do not contain membrane-bound organelles

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24
Q

What are Eukaryotic cells?

A
  • have a membrane-enclosed nucleus
  • have a series of membrane-bound organelles that carry out the functions of the cell as directed by the genetic information contained in the nucleus.
  • more complex of the two cell types.
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25
Q

What are the main components of a typical cell?

A

See screenshot called “cell components”

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26
Q

What is a nucleus?

A
  • first of the organelles

- contains the DNA of the cell in organized masses called chromosomes.

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27
Q

What is a chromosome?

A
  • Compact, rod-shaped bodies located within the nucleus of a cell.
  • contain DNA/all of the genetic information for the regeneration(repair and replication) of the cell
  • contain all instructions for the function of the cell.
  • Every organism has a characteristic number of chromosomes specific to the particular species.
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28
Q

What are ribosomes?

A
  • organelles that read the RNA produced in the nucleus and translate the genetic instructions to produce proteins.
  • Cells with a high rate of protein synthesis generally have a large number of ribosomes.
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29
Q

Where can ribosomes be found?

A
  • can be found in two locations:
    Bound ribosomes are those found attached to the endoplasmic reticulum (ER)
    free ribosomes are those found in the cytoplasm.
        The two types are interchangeable and have identical structures, although they have slightly different roles.
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30
Q

What is the ER?

A

Endoplasmic Reticulum- a membranous organelle found attached to the nuclear membrane and consists of two continuous parts: rough ER and smooth ER

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31
Q

What is rough ER?

A
  • Through an electron microscope, it is clear that this part of the membranous system is covered with ribosomes.
  • it is responsible for protein synthesis and membrane production.
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32
Q

What is smooth ER?

A
  • The other section of the ER that lacks ribosomes

- It functions in the detoxification and metabolism of multiple molecules.

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33
Q

What is the Golgi apparatus?

A
  • a packaging, processing, and shipping organelle inside the cell.
  • transports proteins from the ER throughout the cell.
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34
Q

What are lysosomes?

A
  • Intracellular digestion takes place in lysosomes.
  • Packed with hydrolytic enzymes, the lysosomes can hydrolyze proteins, fats, sugars, and nucleic acids.
  • Lysosomes normally contain an acidic environment (around pH 4.5).
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35
Q

What are vacuoles?

A
  • membrane-enclosed structures that have various functions, depending on cell type.
  • Many cells, through a process called phagocytosis,uptake food through the cell membrane, creating a food vacuole.
  • Plant cells have a central vacuole that functions as storage, waste disposal, protection, and hydrolysis.
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36
Q

What is phagocytosis?

A

Process in which cells engulf food particles through the cell membrane.

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37
Q

What is mitochondria?

A
  • One of the two distinct organelles that produce cell energy: the mitochondrion and the chloroplast.
  • Mitochondria are found in most eukaryotic cells
  • site of cellular respiration.
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38
Q

What are chloroplasts?

A
  • The other of the two distinct organelles that produce cell energy: the mitochondrion and the chloroplast.
  • found in plants and are the site of photosynthesis.
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39
Q

What is the cellular membrane?

A
  • most important component of the cell

- contributing to protection, communication, and the passage of substances into and out of the cell.

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40
Q

What is the cellular membrane made up of?

A

a bilayer of phospholipids with proteins, cholesterol, and glycoproteins peppered throughout

Because phospholipids are amphipathic molecules, this bilayer creates a hydrophobic region between the two layers of lipids, making it selectively permeable.

Many of the proteins, which pass completely through the membrane, act as transport highways for molecular movement into and out of the cell.

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41
Q

What is the plasma membrane made of?

A

a bilayer of phospholipid molecules arranged with their nonpolar “tails” pointing toward each other

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42
Q

What does the cholesterol molecules help stabilize?

A

the flexible bilayer structure to prevent breakage

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43
Q

where can the protein molecules and protein-hybrid molecules be found?

A

the outer or inner surface of the bilayer—or extending all the way through the membrane.

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44
Q

What are the two catabolic pathways that lead to cellular energy production?

A

simple combustion reaction- cellular respiration produces far more energy than fermentation;

fermentation- anaerobic

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45
Q

What is the balanced equation in the simplified chemistry behind respiration?

A

C6H12O6+ 6O2 →6CO2 + 6H2O

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46
Q

What are the simplified three steps of cellular respiration?

A

glycolysis, citric acid cycle, and electron transport system

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47
Q

What is one molecule that is used as the energy currency of the cell?

A

adenosine triphosphate (ATP)

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48
Q

What is another compound that acts as a reducing agent and is a vehicle of stored energy?

A

reducednicotinamide adenine dinucleotide (NADH)

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49
Q

What is NADH?

A

A molecule used as a precursor to produce greater amounts of ATP in the final steps of respiration.

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50
Q

What is the first step in the metabolism of food to cellular energy?

A

the conversion of glucose to pyruvate in a process called glycolysis

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51
Q

What is glycolysis?

A

Anaerobic breakdown of glucose;

first stage in cell respiration.

52
Q

Where does glycolysis occur?

A

cytosol of the cell

53
Q

What does glycolysis produce?

A

two molecules of ATP, pyruvate, and NADH each

54
Q

What is the second step in the metabolism of food to cellular energy?

A

the pyruvate is transported into a mitochondrion and used in the first of a series of reactions called the citric acid cycle (also called the Krebs cycle)

55
Q

What is the citric acid cycle (Krebs cycle)?

A

Series of reactions that occur in the mitochondrion during cellular respiration.

56
Q

Where does the citric acid cycle take place?

A

the matrix of the mitochondria

57
Q

What is produced from one single glucose molecule in the citric acid cycle?

A

two ATP molecules
six molecules of carbon dioxide
six NADH molecules

58
Q

What is the third step in the simplified explanation of the metabolism of food to cellular energy?

A

begins with the oxidation of the NADH molecules to produce oxygen and finally to produce water in a series of steps called the electron transport chain.

59
Q

What is the electron transport chain?

A

Series of steps in cellular respiration that produces water and ATP.

60
Q

In the third step of the simplified explanation of respiration, what is produced from one glucose molecule?

A

28 to 32 ATP molecules

61
Q

In cellular respiration, what is the overall conversion results of one glucose molecule consumed?

A

32 to 36 ATP molecules

62
Q

Summary of cellular respiration

A

This simplified outline of cellular respiration represents one of the most important catabolic pathways in the cell.

Note that one phase (glycolysis) occurs in the cytosol but that the two remaining phases (citric acid cycle and electron transport system) occur within a mitochondrion.

Note also the divergence of the anaerobic and aerobic pathways of cellular respiration.

ADP, Adenosine diphosphate; ATP, adenosine triphosphate;

CoA, coenzyme A;

FAD, flavin adenine dinucleotide; FADH2, form of flavin adenine dinucleotide;

NAD, nicotinamide adenine dinucleotide; NADH, form of nicotinamide adenine dinucleotide.

63
Q

What is photosynthesis?

A

Chemical process that converts light energy to synthesize carbohydrates.

64
Q

In the previous section, the harvesting of energy by the cell was discussed. But where did that energy originate?

A

It began with a glucose molecule and resulted in a large production of energy in the form of ATP. A precursor to the glucose molecule is produced in a process called photosynthesis.

65
Q

What is the chemical equation for photosynthesis?

A

6CO2 + 6H2O + Light energy → C6H12O6 + 6O2

The only notable difference is the addition of light energy on the reactant side of the equation. Just as glucose is used to produce energy, so too must energy be used to produce glucose.

66
Q

Photosynthesis consists of what two stages?

A

the light reactions and the Calvin cycle

67
Q

What are the light reactions in photosynthesis?

A

The light reactions are those that convert solar energy to chemical energy.

The cell accomplishes the production of ATP by absorbing light—>using that energy to split a water molecule—->transfer the electron

= creating nicotinamide adenine dinucleotide phosphate and producing ATP.

These molecules are then used in the Calvin cycle to produce sugar.

68
Q

What is the Calvin cycle in photosynthesis?

A

The sugar produced by the light reactions is polymerized and stored as a polymer of glucose. These sugars are consumed by organisms or by the plant itself to produce energy by cellular respiration.

69
Q

What are the raw materials for cellular respiration?

A

glucose and oxygen

70
Q

What are the products of cell respiration?

A

water, carbon dioxide, and ATP

71
Q

What are the raw materials of photosynthesis?

A

water, carbon dioxide

72
Q

What are the products of photosynthesis?

A

oxygen, glucose

73
Q

How is cell respiration and photosynthesis cyclical?

A

the raw materials for one process are the products of the other process.

The raw materials for cellular respiration are glucose and oxygen, whereas the products of cell respiration are water, carbon dioxide, and ATP. Plants and other autotrophs will utilize the products of cell respiration (water, carbon dioxide) in the process of photosynthesis. The products of photosynthesis (oxygen, glucose) become the raw materials of cell respiration.

74
Q

Cells reproduce by three different processes, all of which fall into what two categories?

A

sexual and asexual reproduction.

75
Q

What are the two types of asexual reproduction?

A

binary fission

mitosis

76
Q

Explain binary fission.

A

Bacteria cells reproduce asexually this way.

The chromosome binds to the plasma membrane where it replicates. Then as the cell grows, it pinches in two, producing two identical cells .

A single cell separates into two identical daughter cells, each with an identical copy of parent DNA.

77
Q

What are the 5 stages of mitosis?

A

prophase, prometaphase, metaphase, anaphase, and telophase

78
Q

What is mitosis?

A

This process of cell division occurs in five stages before pinching in two in a process called cytokinesis.

79
Q

What happens during prophase?

A

the chromosomes are visibly separate, and each duplicated chromosome has two noticeable sister chromatids.

80
Q

What happens in prometaphase?

A

the nuclear envelope begins to disappear, and the chromosomes begin to attach to the spindle that is forming along the axis of the cell.

81
Q

What happens in metaphase?

A

all the chromosomes align along what is called the metaphase plate or the center of the cell.

82
Q

What is a metaphase plate?

A

Disk formed during metaphase in which the chromosomes align on equatorial plane of the cell.

83
Q

What happens in anaphase?

A

begins when chromosomes start to separate. In this phase, the chromatids are considered separate chromosomes.

84
Q

What happens in telophase?

A

chromosomes gather on either side of the now separating cell. This is the end of mitosis.

85
Q

What happens in cytokinesis?

A
  • The second process associated with cell division
  • separate phase from the phases of mitosis
  • The cell pinches in two, forming two separate identical cells.
86
Q

How is asexual reproduction different from sexual reproduction?

A

In asexual reproduction, the offspring originates from a single cell, yielding all cells produced to be identical.

In sexual reproduction, two cells contribute genetic material, resulting in significantly greater variation. These two cells find and fertilize each other randomly, making it virtually impossible for cells to be alike.

87
Q

What is meiosis?

A

The special cell division that takes place in the gonads (ovaries and testes) as part of sexual reproduction. In the process, the chromosome number is reduced from 46 to 23, so when the egg and the sperm unite in fertilization, the zygote will have the correct number of chromosomes.

88
Q

What are the stages and results of meiosis?

A

meiosis I, meiosis II

resulting in four daughter cells. Each of these daughter cells contains half as many chromosomes as the parent.

89
Q

What happens during interphase?

A

Stage of the cell cycle during which growth and DNA synthesis occur.

the chromosomes are duplicated and the cell prepares for division.

90
Q

Who first discovered the first basic principles of genetics and by using what?

A

Gregor Mendel

garden peas

91
Q

What are alleles?

A

Alternate versions of a gene.

92
Q

What are two types of alleles for simple traits?

A

dominant, recessive

93
Q

What is homozygous?

A

Trait in an organism that contains identical alleles.

94
Q

If both of the alleles are the same type, the organism is said to be ______ for that trait.

A

homozygous

95
Q

If both of the alleles are different types, the organism is said to be _______.

A

heterozygous

96
Q

What is heterozygous?

A

Trait in an organism that contains different alleles.

97
Q

If an allele is ______ for a particular trait, the letter chosen to represent that allele is _____. If the allele is ______, then the letter is ______.

A

dominant
capitalized
recessive
lowercased

98
Q

If a ______ allele is present, then the phenotype expressed will be the _____. The only way a ______ trait will be expressed is if both alleles are ______.

A

dominant
dominant
recessive
recessive

99
Q

What is a Punnett square?

A

Grid used to predict genotype and phenotype of the offspring of sexual reproduction.

100
Q

What is a genotype?

A

the combination of alleles

101
Q

What is a phenotype?

A

what traits will be expressed

102
Q

Genetics is the study of what?

A

heredity

103
Q

What are some other methods of genetic expression?

A

multiple alleles
pleiotropy
epistasis
polygenic inheritance

104
Q

Many human disorders can be detected by studying a person’s _____ or by creating a _____.

A

chromosomes

pedigree

105
Q

What is a pedigree in biology?

A

a family tree that traces the occurrence of a certain trait through several generations.

106
Q

What is a pedigree useful in understanding?

A

the genetic past as well as the possible future.

107
Q

What are the four nitrogenous bases in DNA?

A

adenine, thymine, guanine, and cytosine

108
Q

Who described the structure of DNA in 1953?

A

Watson and Crick

109
Q

In DNA, Adenine bonds with _____ , and _____ bonds with cytosine

A

thymine
guanine

A-T
G-C

110
Q

Each gene along a strand of DNA is a template for what?

A

protein synthesis

111
Q

What is the first process in protein synthesis?

A

transcription

112
Q

What happens during transcription?

A

Process during protein synthesis in which the DNA molecule is used as a template to form mRNA.

An RNA strand, complementary to the original strand of DNA, is produced called mRNA.

113
Q

What is mRNA?

A

messenger RNA
Type of RNA formed from a template of DNA;
carries coded information to form proteins.

114
Q

What are the nitrogenous bases of RNA and its pairing?

A

The RNA strand has nitrogenous bases identical to those in DNA with the exception of uracil, which is substituted for thymine.

Adenine bonds with uracil , and guanine bonds with cytosine.

A-U
G-C

115
Q

What is the function of mRNA?

A

a messenger from the original DNA helix in the nucleus to the ribosomes in the cytosol or on the rough ER.

116
Q

What is a codon?

A

Three-base sequence of messenger RNA.

each of these codes for a specific amino acid

117
Q

Where is the site of translation?

A

the ribosomes in the cytosol or rough ER

118
Q

Where is the anticodon located?

A

on a unit called transfer RNA (tRNA), which carries a specific amino acid

119
Q

What is tRNA?

A

RNA involved in protein synthesis; transfers a specific amino acid to the ribosome and binds it to mRNA.

120
Q

multiple _____ molecules bind in order and are released by the ____.

A

tRNA

ribosome

121
Q

What is stop codon?

A

Sequence of bases that terminates translation during protein synthesis.

122
Q

In DNA replication, when a DNA molecule makes a copy of itself, why does it “unzip”?

A

to expose its nucleotide bases

123
Q

The mechanism of obligatory base pairing is coordinated by what enzyme?

A

DNA polymerase

124
Q

What happens during the mechanism of obligatory base pairing?

A

New DNA nucleotides bind to the exposed bases which forms a new “other half” to each half of the original molecule. After all the bases have new nucleotides bound to them, two identical DNA molecules will be ready for distribution to the two daughter cells.

125
Q

What is a polypeptide?

A

long strands of peptide bonds;

Several polypeptide chains may be needed to make a complete protein molecule.

HESI (2 decks)

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