UWC Chapter 1 Exam

What is cancer caused by?

A change in events of the cell cycle.

What are the stages of the Cell Cycle?

G1 (growing, metabolizing)

Sphase (duplicate genetic material)

G2(growth, metabolism)

MPhase (cell division)

Examples of organelles:

Nucleus,

Mitochondria

Endoplasmic recticulum

Plasma membrane

Matter

anything that has mass and takes up space, forming the physical substance of all living organisms, from atoms to complex molecules like DNA and cells.

Element

Made up of all the same types of atoms.

Atom

The smaller unit possible in which properties are maintained. They bond together with covalent bonds to form molecules.

How to calculate atomic mass number

Add the protons and neutrons

molecule

Group of atoms bonded together, representing the smallest fundamental unit of a chemical compound that can take part in a chemical reaction.

covalent bond

Chemical link formed when two atoms share one or more valence electrons to achieve stability and fill their outer electron shells.

What are the basic macromolecules needed for life?

Lipids, Carbohydrates, Proteins, DNA/RNA (nucleic acids)

What are proteins and what are their purpose?

large, complex biomolecules composed of long chains of amino acids (linked by peptide bonds) that act as essential molecular machines for nearly all cellular functions. They are crucial for building, repairing, and maintaining tissues, acting as enzymes, structural components, and transporters. 

What are nucleic acids and what are their purpose?

large, essential biomolecules—specifically DNA and RNA—that store, transmit, and express genetic information in all living cells and viruses

Where is DNA always located?

Nucleus

What is the basic structure of a nucleotide?

phosphate, deoxyribose, and a nitrogenous base.

What is the basic structure of DNA?

a double-stranded helix, resembling a twisted ladder, composed of repeating subunits called nucleotides. Each strand has a backbone of alternating deoxyribose sugar and phosphate groups. The "rungs" of the ladder consist of paired nitrogenous bases—adenine (A) with thymine (T), and cytosine (C) with guanine (G)—held together by hydrogen bonds. 

4 bases found in DNA

adenine (A), cytosine (C), guanine (G), and thymine (T

What are the base pairing rules?

Adenine is paired with Thymine and Cytosine is paired with Guanine

Gene expression

the process where a cell uses DNA instructions to build functional products, usually proteins, through two main steps: transcription (DNA copied to mRNA) and translation (mRNA read to make protein)

Steps from transcription to RNA splicing to translation. Where do each occur

Transcription (Nucleus): RNA polymerase binds to DNA (promoter), separating strands and creating a complementary pre-mRNA molecule from the DNA template.

RNA Splicing & Processing (Nucleus): Before leaving the nucleus, the pre-mRNA is modified: a

5′5′ cap and poly-A tail are added, and non-coding sequences (introns) are removed while coding sequences (exons) are joined together.

Export & Translation (Cytoplasm): The mature mRNA moves from the nucleus to the cytoplasm. Ribosomes read the mRNA codon by codon, using tRNA to bring the correct amino acids, which are joined to form a protein chain. 

What are up-regulated genes?

genes that show an increased level of expression (higher production of mRNA and/or protein) in a cell, usually in response to a specific signal, stress, or change in condition

What are down regulated genes?

genes whose activity—specifically, the production of RNA and proteins—is decreased or suppressed in a cell in response to a stimulus, such as a drug, environmental change, or disease

Gene

a basic unit of heredity, a segment of DNA that carries instructions for building and operating an organism, determining traits like eye color or height by coding for specific proteins, though some genes regulate others

Chromosome

thread-like structures composed of DNA and proteins (histones) located inside the nucleus of eukaryotic cells, serving as the organized, compact package for genetic information

Allele

a different version or variant of the same gene, located at the same spot (locus) on a chromosome

Homologous chromosomes

pairs of matching chromosomes in diploid organisms with one inherited from each parent.

heterozygous

individual inherits two different alleles of a specific gene from their parent.

homozygous

inheriting identical alleles of a specific gene from both biological parents resulting in two identical alleles for a trait.

RNA

single stranded, has uracil in the nitrogenous base

DNA

Double stranded helices; has thymine in the nitrogenous base

Which of the following macromolecules include DNA and RNA?:

Nucleic acids, Proteins, Carbohydrates, Lipids

Nucleic Acids

If an atom has 8 protons and has an atomic mass number of 16, how many neutrons would this atom have? : 8, 12, 16, 0

8

Which of the following organelles contains DNA?

Nucleus

During Translation, _______ facilitates carrying of the amino acids to the _________, which is located in the__________.

tRNA; ribosome; cytoplasm

Given the DNA sequence ATGCATCATCGATC, give the correct complementary DNA sequence.

TACGTAGTAGCTAG

phospholid

crucial structural lipids forming the, bilayer of all cell and organelle membranes, essential for cell integrity and regulating molecular transport.

Composed of a hydrophilic phosphate head and two hydrophobic fatty acid tails,

hydrophobic

nonpolar substances that repel water, often described as "water-fearing" because they do not mix with or dissolve in water.

hydrophilic

substances have a strong affinity for water, readily interacting with or dissolving in aqueous environments due to their polar or charged nature.

These molecules form hydrogen bonds with water, which is essential for nutrient transport, enzyme activity, and forming the outer, water-facing layers of cell membranes. 

Steps of meiosis

Meiosis involves two rounds of cell division (Meiosis I and Meiosis II) that reduce a diploid cell to four unique haploid gametes (sperm or egg), with stages including Prophase, Metaphase, Anaphase, and Telophase (PMAT) in each division, plus cytokinesis, creating genetic diversity through crossing over in Prophase I and independent assortment. Meiosis I separates homologous chromosomes, while Meiosis II separates sister chromatids, similar to mitosis. 

Before Meiosis: Interphase

• The cell grows, copies its DNA (S phase), and prepares for division. 

Meiosis I: Homologous Chromosomes Separate

1. Prophase I:

   Chromosomes condense and pair up (synapsis), forming tetrads.Homologous chromosomes exchange genetic material (crossing over), creating new allele combinations. The nuclear envelope breaks down. 

2. Metaphase I:

   Tetrads line up along the cell's equator (metaphase plate). 

3. Anaphase I:

   Homologous chromosomes (still with sister chromatids) are pulled to opposite poles. 

4. Telophase I & Cytokinesis:

   Chromosomes arrive at poles, nuclear envelopes reform, and the cell divides into two haploid daughter cells, each with duplicated chromosomes. 

Meiosis II: Sister Chromatids Separate

• (No DNA replication occurs between Meiosis I and II). 

1. Prophase II:

   Chromosomes condense again in the two new cells; nuclear envelopes break down. 

2. Metaphase II:

   Chromosomes (each with two chromatids) line up at the equator. 

3. Anaphase II:

   Sister chromatids separate and move to opposite poles, becoming individual chromosomes. 

4. Telophase II & Cytokinesis:

   Chromosomes decondense, nuclear envelopes reform, and the cells divide, resulting in four unique haploid cells (gametes)

Which cells undergo meiosis

Sperm cells

Steps of mitosis

Mitosis is the process of cell division resulting in two genetically identical daughter cells, consisting of four main stages: prophase, metaphase, anaphase, and telophase. Key steps include chromosome condensation, spindle fiber attachment, alignment at the cell equator, separation of sister chromatids, and the reformation of nuclear envelopes. 

Here are the detailed steps of mitosis in order:

• Prophase: Chromosomes condense into X-shaped structures, becoming visible under a microscope. The nuclear envelope breaks down, and the mitotic spindle (microtubules) forms and extends between centrosomes, which move to opposite poles of the cell.

• Prometaphase (Sometimes considered part of Prophase): Microtubules attach to the kinetochores on the chromosomes.

• Metaphase: Chromosomes line up single-file along the metaphase plate (the equator of the cell). Spindle fibers ensure equal separation, attaching to each sister chromatid.

• Anaphase: Sister chromatids are pulled apart by the spindle fibers and move to opposite ends of the cell. Once separated, they are considered individual chromosomes.

• Telophase: Chromosomes arrive at opposite poles, and new nuclear envelopes reform around each set of chromosomes. The chromosomes begin to decondense.

• Cytokinesis: While technically a separate, concluding process, cytokinesis usually begins during late anaphase or telophase, splitting the cytoplasm to create two distinct daughter cells. 

Which cells go through mitosis

Somatic cells

What is a protein that is important during S phase

Homozygous

an individual inheriting identical forms (alleles) of a specific gene from both parents

Heterozygous

having two different alleles (variants) of a particular gene at a specific locus on homologous chromosomes, typically inherited from different parents

Homologous chromosomes

pairs of matching chromosomes in diploid organisms, with one inherited from each parent.

What situation would cause up regulation of genes

increased transcription in response to specific cellular stimuli, such as environmental stress, hormonal changes, or a deficiency in receptors, allowing cells to adapt or maintain homeostasis

What situation would cause down regulation of genes

a decrease in gene expression or activity, is primarily triggered by cellular adaptation to environmental stress (e.g., pollutants, UV light), chronic hormone exposure, or drug intake, leading to reduced receptor density

When can other alterations occur during gene expression

at almost any stage—from DNA structure to post-translational protein modification—driven by environmental, genetic, or developmental factors. Key moments include epigenetic modifications (methylation/histone modification), alternative splicing, RNA interference (microRNAs), and translational regulation during cellular stress. 

mutation

a permanent change in an organism's DNA sequence, acting as the ultimate source of all genetic variation, which can arise from errors in DNA replication, environmental factors, or radiation

Transcription

the crucial first step of gene expression where a cell makes an RNA copy (messenger RNA or mRNA) from a specific DNA segment,

RNA splicing

a crucial biological process where non-coding regions (introns) are removed from a precursor messenger RNA (pre-mRNA) transcript, and the remaining coding regions (exons) are joined together to form a mature mRNA, allowing a single gene to produce multiple different proteins through alternative splicin

Translation

the fundamental biological process in which ribosomes in the cytoplasm or rough endoplasmic reticulum synthesize proteins by decoding messenger RNA (mRNA) sequences

Components of a nucleotide

phosphate, deoxyribose, nitrogenous base

Which of the following macromolecules include DNA and RNA?

nucleic acids

Which of the following organelles contains DNA?

Nucleus

During telophase

the nuclear membrane reforms

For an element that has an atomic number of 7, how many electrons would each of its atoms have?

Impossible to determine.

For an element that has an atomic number of 7, how many neutrons would each of its atoms have?

Impossible to determine

A phospholipid is an example of a

lipid

Crossing over occurs in

Prophase I

For a cell that begins with 46 chromosomes, at the end of Meiosis II, each daughter cell will have ____________number of chromosomes and these chromosomes will be ______________

23; unduplicated

Given a cell with 46 chromosomes before the start of mitosis, would chromosomes be duplicated or unduplicated in each daughter cell after mitosis? (This question implies that everything about mitosis was normal)

Unduplicated

Mass number

the number of protons plus neutrons

Molecule

group of atoms bonded together with covalent bonds. provide function within a cell.

Macromolecules examples

Lipids, proteins, carbohydrates, nucleic acids

 Gene expression

transcribing the genetic instructions in the gene to RNA and then translating it to proteins to allow it to be able to work in its environment. This involves transcription, RNA splicing, and translation.

During transcription, the _________ uses the DNA strand as a template to form the _________.

nucleus, RNA single strand.

gene

describes sequences that are individual and are responsible for encoding a protein

A sugar is a monomer of _________, a type of macromolecule

carbohydrates

Nucleotides are building blocks that make up _________, a macromolecule.

nucleic acids

If the atomic number of a particular element is 7, how many protons would each of its atoms have?

7 protons

Where does translation occur

Ribosomes

Translation

the process of creating proteins by mRNA being translated into amino acids.

What direction (5' to 3' or 3' to 5') is the DNA that undergoes transcription?

3’ to 5’

What type of interaction holds the two strands of DNA together between the nitrogenous bases?

hydrogen bonds

Are the bonds between the phosphates of the single strand of DNA covalent bonds or hydrogen bonds?

covalent bonds

Silent mutation

allows the nucleotide to change but the amino acids

do not.

microRNA

version of RNA molecules that are very small that bind to mRNA and stop it from making proteins which can lead to different illnesses like cancer.

receptors

protein molecules that bind to ligands and affect the cell

ligands

molecules that bind to a protein to set off a cellular response.

Electrons mass

negligible

electrons/sharing of electrons between atoms

covalent bonds

An atom has 6 protons and 6 neutrons. What is its mass?

12

Going from DNA to RNA is called

transcription

Transcription is in the

nucleus

RNA splicing is in the

nucleus

Translation is in the

Ribosomes/Rough ER/Cytoplasm

Crossing over only happens in

meiosis during prophase 1. Sharing chromosomes pieces between homologous pairs

mitosis

somatic cells: cell division to replace cells with an identical copy of what was there before

What does mitosis start with

a cell that has duplicated chromosomes

what does mitosis end with

with an identical cell that has unduplicated chromosomes

Meiosis

egg and sperm cell: to produce cells with half of genetic information so when egg and sperm fuse it has organisms with 46 chromosomes.

Meiosis 1 start with

duplicated chromosomes (diploid)

Meiosis 1 End with

still have duplicated chromosomes (diploid) but half the chromes present (haploid)

Meiosis II start with

half of the amount of chromosomes still duplicated

Meiosis II end with

half the amount of chromosomes unduplicated

G1

growth, metabolism, chromosomes-unduplicated

G2

growth, metabolism, duplicated chromosomes

SPhase

DNA replication, DNA polymerase is important here