Biology Chapter 2: Cells, Cell Division, and Cell Specialization Flashcards
Cytoplasm Structure
- Mostly water with other substances
- Chemical reactions make it jelly-like to liquid
Cytoplasm Function
- Space to contain organelles
- Allows organelles to move (flow) through the cell
Cell Membrane Structure
- Duel layer, made up of proteins and lipids (fats)
- Flexible, plasma membrane - fluid mosaic model
Cell Membrane Function
- Boundary of the cell, support
- Selectively permeable, controls what goes in and out
- Allows some substances to enter (water, oxygen), but not others
Cell Wall Structure
- Outside cell membrane
- Made of cellulose
Cell Wall Function
- Provides structure and support for the cell
- Protection
Nucleus Structure
- roughly spherical
- largest organelle in animal cells
- surrounded by nuclear membrane
- DNA (deoxyribonucleic acid) inside it
Nucleus Function
- Controls all functions of cell
- Directs cell division and formation of cell structures
- DNA carries coded instructions for all cell activity
Mitochondria Structure
- Oval (bean) shaped
- Can be 1 or more depending on need
Mitochondria Function
- Contain enzymes to to convert stored energy to usable energy (glucose) through cellular respiration
- Make energy available to the cell
- Active cells have more mitochondria
Endoplasmic Reticulum Structure
- 3D network of branching tubes & pockets
Endoplasmic Reticulum Function
- Fluid-filled tubes transport materials through the cell
- Connects nuclear membrane to cell membrane
Vacuole Structure
- Membranous fluid-filled sac
Vacuole Function
- Stores or removes substances from the cell
- In plants, stores a significant amount of water
- When these are full of water, the plant’s stems and leaves are firm.
- If the water level drops, the vacuoles lose pressure and the cells become soft. The stems and leaves become droopy until the water is replaced.
Golgi Bodies Structure
- Looks like a stack of pancakes
Golgi Bodies Function
- Collect and process materials to be removed from cell
- Makes and secretes mucous
Chloroplast Structure
- Contains chlorophyll (green pigment)
Chloroplast Function
- Absorbs light (solar) energy, used to make own food for plants (photosynthesis)
Cell Theory
- All living things are made up of one or
more cells. - The cell is the simplest unit that can carry
out all life processes. - All cells come from other cells.
Types of Cells
- Prokaryotes
- Eukaryotes
Qualities of Prokaryotes
- All are unicellular
- Includes Eubacteria and Archaebacteria
- Structurally simple:
1. Lack a nucleus
2. Lack membranous organelles
Qualities of Eukaryotes
- Unicellular or multicellular
- Includes plants, animals, fungi and protists
- Contain:
1. Membrane-bound nucleus
2. Numerous membrane-bound organelles:
Mitochondria
Golgi apparatus
Endoplasmic reticulum (ER)
Vacuoles
Organelle
- a cell structure that performs a
specific function for the cell
Asexual reproduction
- the process of producing offspring from only one parent
- the production of offspring that are
genetically identical to the parent - Cell division called mitosis
Sexual reproduction
- Genetic information from two cells is combined to form a new organism.
- Generally involves two specialized sex cells (gametes) that unite to form a zygote.
- Gametes are formed through a process called MEIOSIS.
Examples: - Vertebrate animals
- Plants (with cones, flowers)
Interphase
The phase of the cell cycle
during which the cell performs its normal
functions and its genetic material is copied
in preparation for the cell division
Mitosis
The stage of the cell cycle in which the DNA in the nucleus is divided; the first part of cell division
Daughter cell
One of two genetically identical, new cells that result from the division of one parent cell
Chromosome
A structure in the cell nucleus made up of a portion of the cell’s
DNA, condensed into a structure that is
visible under a light microscope
Chromatid
One of two identical strands of
DNA that make up a chromosome
Centromere
The structure that holds
chromatids together as chromosomes
Prophase
The DNA condenses, becoming shorter
and thicker and forming chromosomes. Each
chromosome is made up of two identical chromatids. The nuclear membrane starts to dissolve, releasing the chromosomes into the cytoplasm.
Metaphase
The chromosomes line up along the
middle of the cell. The nuclear membrane
completely dissolves.
Anaphase
Each chromosome separates into two identical single stranded parts (formerly the chromatids; now the daughter chromosomes). The spindle fibres pull the daughter chromosomes toward each end of the cell.
Telophase
The chromosomes reach opposite ends of the cell and start to lengthen. A new nuclear membrane begins to form around each of the chromosomes.
Cytokinesis
The cell’s cytoplasm divides. In an animal cell,
the cell is pinched off in the centre, forming two new daughter cells. In a plant cell, a plate
forms that becomes a cell wall, sealing off the contents of the new cells from each other.
Note: The two new daughter cells subsequently enter interphase (the cycle repeats).
Cancer
When cells grow and divide out of control, they cause a group of diseases
called cancer
Tumour
A mass of cells that continue
to grow and divide without any obvious
function in the body
Benign tumour
A tumour that does not affect surrounding tissues other than by physically crowding them
Malignant tumour
A tumour that interferes with the functioning of surrounding cells; a cancerous tumour
Metastasis
The process of cancer
cells breaking away from the original
(primary) tumour and establishing another
(secondary) tumour elsewhere in the body
Mutation
A random change in the DNA
Carcinogen
Any environmental factor that
causes cancer
Pap test
a test that involves taking a sample of cervical cells to determine if they are growing abnormally
Why screen for cancer?
It increases the chance of detecting cancer early enough to successfully treat it.
Methods of Cancer Screening
- Imaging Techniques - includes endoscopy, X-ray, ultrasound, CT scanning, and MRI.
- Examining Cells (biopsy) - examine a sample of the suspected cancer cells under a microscope. This is
the only way to confirm a diagnosis of cancer.
Treatments for Cancer: Chemotherapy
- Chemotherapy - treating cancer using drugs. Slows/stops the cancer cells from dividing and spreading to other parts of the body, and by killing the cells (causes hair loss, nausea, fatigue)
Treatments for Cancer: Surgery
- Surgery - physically removing the cancerous tissue (if tumour is easily accessible)
Treatments for Cancer: Radiation
- Radiation is directed at the tumour either by using a focused beam or by implanting a radioactive source into the tumour (cancer cells damaged easily because of their rapid division)
Treatments for Cancer: Biophotonics
- uses beams of light to detect and treat cancer (living cells and organisms).
- more accurate and sensitive than radiation
Specialized Cell
A cell that can perform a specific function
Red Blood Cells
- Contains hemoglobin (pigment) for the transportation of oxygen in the blood.
- smooth, donut shaped cell lacking nucleus
Goblet Cells (trachea)
- Help keep dirt out of the lungs.
- Secret mucous to trap dirt and have cilia (hair like
extensions) to help move it out of the respiratory system.
Muscle Cells
- Attached to bones, these cells contract to allow movement.
- arranged in bundle called fibres
Fat Cells
- Contains a large vacuole for storage of chemical energy
White Blood Cells
- Can move to engulf bacteria and fight infection
Skin Cells
- Covers outside of the body to protect internal cells and reduce water loss
- layered tightly together
Bone Cells
Collect calcium from food and build upon itself to create the body’s skeleton
Sperm Cells
- Move independently to carry DNA from the male parent to join with an egg cell from the female parent
Photophores
- Cells that can emit light (ex. for attracting mates)
Nerve Cells
- Conduct electrical impulses to coordinate body activity
- Long, thin cell with many branches
Diffusion
A transport mechanism for
moving chemicals into and out of the cell,
from an area of higher concentration to an
area of lower concentration
Osmosis
The movement of a fluid, usually
water, across a membrane toward an area
of high solute concentration
What do both plant and animal cells need?
- Plant and animal cells all need the same things: a source of energy, nutrients, water, and gases.
- Many chemicals need to be in a solution (dissolved in water) so that they can be used in chemical reactions within the cell.
ABCD of Moles
Checking for suspicious mole growths, which can indicate the existence of a benign or malignant tumour.
* A = Asymmetry
* B = Border
* C = Colour
* D = Diameter
