Cancer and Science Study Guide

Explain why the process of science is more like a pinball machine than a ladder

It’s unpredictable, and the research process can be non-linear. There’s also many ways to find the answer (kinda like there’s many ways to play a pinball machine)

Hypothesis

testable prediction that’s made before any research has been done

Theory

explains things that’s already been shown by data

Data

Info you collect during an investigation or experiment

First step of the scientific process

Asking a question

Second step of the scientific process

Making a hypothesis

Third step of the scientific process

Designing your experiment

Fourth step of scientific process

Collecting data

Fifth Step of Scientific Process

Evaluate whether or not the hypothesis was supported

Sixth step of Scientific Process

Ask your peers to review your data and conclusions

Seventh step of Scientific Process

Ask more questions

Cancer

Body’s inability to control cell division

Characteristics of Cancer cells

ability to grow uncontrollably, avoids normal cell death (apoptosis), spreads to other tissues (metastasis)

Apoptosis

programmed cell death

Metastasis

cancerous cells spread further from the original site

Melanoma

On skin

Leukemia

White blood cells on bone marrow

Carcinoma

Lining of the internal organs or skins

Sarcoma

Connective tissue, such as bone

Lymphona

Cells and tissues of immune system

Why is all cancer genetic?

Involves harmful or inherited mutations that disrupt cell growth

Cell

 smallest unit of biological organization that has all units of life

What are 5 things that all cells must do?

1. Ability to acquire energy

2. Ability to respond to environment

3. Ability to respond 

4. Ability to maintain an internal environment

5. Ability to adapt to its environment

4 features ALL cells have

plasma membrane, cytoplasm, DNA, ribosomes

Plasma membrane

protects (encloses) the DNA

Cytoplasm

containing jelly-like cytosol

DNA

cell’s genetic material

ribosomes

responsible for protein synthesis

 Prokaryotic

Bacteria and Archaea

Eukaryotic

Protists, Fungi, Plants, Animals

Nucleus

Contains the genetic information of the cell

Ribosomes

Structures where the genetic info is used to manufacture proteins

Which two organelles share the general function of info processing

nucleus and ribosomes

Mitochondria

Convert the energy found in nutrients to form usable by the cell

Which organelle has the general function of energy

Mitochondria

Which organelles has the general function of transport and processing nutrients

Endoplasmic reticulum (ER), lysosome, golgi apparatus

Endoplasmic Reticulum (ER)

acts as a transport system for proteins and other molecules, plays a key role in lipids and calcium storage

Rough ER

synthesize, modify, sort, and fold proteins

Smooth ER

responsible for lipid synthesis (cholesterol), steroid hormone production, carbs metabolism, calcium storage and release, detoxifies waste

Difference between Smooth ER and Rough ER

Smooth ER doesn’t have ribosomes, while Rough ER does

synthesis

process of creating or building complex molecules from simpler substances (think building blocks)

Lysosomes

Digestion of incoming nutrients

Which organelle has the general function of isolation

Plasma membrane

Which organelle has the general function of cell division

Centrioles

Function of plasma membrane

Isolates the cell from its external environment and selectively allows for the passage of materials

Function of centrioles

Assist in dividing the genetic materials and contents of the cell during cellular reproduction

What does it mean for a cell to become specialized?

When cells divide, they receive signals from nearby cells that instruct them to turn off genetic instructions. Because of this, cells become more specialized and allows them to form tissues and organs

What does the “cell cycle” refer to?

The process of cell division (the process of our bodies making copies of our cells to replace the worn out ones)

Does a cell spend most of its time in interphase or M phase?

Interphase

What happens in G1

growth and normal function

What happens in S phase

DNA replication

What happens in G2 phase

further growth and prep for mitosis

What happens in M phase

mitosis and cell division

What happens in G0

Resting phase - cells stop dividing and start performing their assigned functions

Which phases are part of interphase?

G1, S and G2

Visual of Interphase

Purpose of interphase

Grow the cell and prepare it for division by replicating its DNA and synthesizing necessary proteins and organelles

Visual of prophase

Purpose of prophase

Prepare the cell for division by condensing the duplicated DNA into visible chromosomes, forming the spindle apparatus and preparing the nuclear envelope to break down

What happens during prophase

Spindle fibers from pole attach to the chromosomes

What happens during interphase

• Eukaryotic cells duplicate and the contents of the cytoplasm

• DNA replicates in nucleus

• Pair of centrioles is outside the nucleus

Visual of metaphase

Purpose of metaphase

Chromosomes are aligned at the spindle equator midway between the spindle poles

What’s happening during metaphase

The duplicated chromosomes are aligned at the center of the cell

Visual of anaphase

Purpose of anaphase

Sister chromatids separate and become daughter chromosomes (each pole gets a set of daughter chromosomes)

What happens in anaphase

• Centromeres break down and spindle fibers shorten, making chromosomes move towards the pole

• Each side of cell has a complete and identical set of chromosome

Final stage of cell cycle

Telophase

Visual of cytokinesis

Purpose of cytokinesis

Final step. Divides two distinct daughter cells

What happens during cytokinesis

The cytoplasm splits, physically dividing the original parent cell into two separate cells. 

During which phase do mutations arise?

S phase (DNA replication)

When a cell is in G0, it carries out all its regular functions except what?

Doesn’t divide or prepare to divide

What are cell cycle checkpoints and what is their general purpose/importance?

crucial control points that ensure the accuracy and proper execution of cell division, allowing the cell to pause and assess its internal and external conditions before proceeding to the next phase

 If a cell can’t repair its DNA, what should it do?

Apoptosis

Why does it make sense that DNA must be copied before a cell can divide?

to ensure that each resulting daughter cell receives a complete and identical set of genetic instructions from the parent cell

What’s a sister chromatid?

one of two identical copies of a replicated chromosome, joined together at the centromere

What does M phase consist of?

mitosis and cytokinesis

Define cleavage furrow

a shallow groove or indentation that forms on the surface of an animal cell membrane during cytokinesis (the division of the cytoplasm) to divide the cell into two daughter cells

Define cell plate

disc-shaped structure that forms in the middle of a dividing plant cell during cytokinesis, which eventually develops into a new cell wall separating the two daughter cells

Which structure is found in cells without walls (like animal cells)?

centrioles, lysosomes, centrosomes

Which is found in cells with walls (like plant cells)?

cellulose and chloroplasts

What are four reasons that cells must divide?

to achieve growth and development into a multicellular organism, to repair and replace damaged or worn-out cells, to reproduce, and to allow for the regeneration of tissues or limbs in some organisms

What’s a mutation

Permanent change in a cell’s DNA or the structure/number of chromosomes

Define mutagen

an agent that causes mutations or changes in the DNA’s cell. Examples are UV radiation and X-Rays (which are physical agents), or pesticides (chemical agents)

Define carcinogen

Substance or agent that can cause cancer

How can a change in the DNA code/information ultimately result in a change to a protein?

by changing the sequence of amino acids it’s built from

How can the change in a protein result in a change in cell behavior?

It can affect it by changing its structure, function, concentration, localization

 What are the normal roles of a tumor suppressor (TS) genes

Responsible for preventing unregulated cell growth.

What proteins do TS code

p53 and BRCA1

 How can a change in a TS gene lead to a cell having new characteristics that can ultimately lead to cancer?

By removing the “brakes” on cell growth

What is the role of proto-oncogene genes and the proteins they code for?

They signal pathways that are designed to promote growth and development

How can a change in a proto-oncogene (which would now be called an oncogene) lead to a cell having new characteristics that can ultimately lead to cancer?

When a mutation causes it to be in an active state without the influence of the growth factor, or causes it to be more sensitive to the influence of a hormone

Which analogy is how an oncogene leads to unregulated cell division?

stuck gas pedal in a car

Which analogy is how a mutated tumor suppressor gene leads to unregulated cell division?

non-functional brake pedal

Why does it take time for a cell to become cancerous?

it's a multi-step process that requires the accumulation of multiple genetic mutations and abnormalities within a single cell, rather than a single event

Cancer cells are immortal. What does that mean?

they can indefinitely divide and multiply due to genetic mutations that activate the enzyme telomerase, which prevents the protective caps on the ends of chromosomes (telomeres) from shortening with each division

Why is a cancer cell being immortal a problem?

it allows for uncontrolled proliferation, leading to massive, potentially metastatic tumors that can disrupt normal body functions and spread to other tissues

What of these characteristics do benign and malignant tumors share?

Cancerous, non-cancerous, cells don’t die enough, cells divide too much, cells become unspecialized,

What characteristics distinguish them?

tumor is localized (in one place), tumor is invasive (moving into at least nearby tissue where it’s not supposed to be)