Chapter 6- cells Flashcards
Photosynthesis equation
6 CO2 + 6 H2O + light —-> C6H12O2 + 6 O2
Photosynthesis
Process by which a cell captures energy in sunlight (make it into chemical energy) and uses it to make food
Autotroph
An organism which makes their own food
Heterotroph
An organism which relies on other organisms to get food
Stage 1 (photosynthesis)
Chloroplasts in plant cells capture energy from the sun using photosynthesis pigment called chlorophyll (this energy is used to power stage 2)
Stage 2 (photosynthesis)
CO2 (which enters through the stomata) and H2O ( which enters through roots) undergo a chemical reaction in chloroplasts to produce sugars (Oxygen leaves through the stomata)
What are the reactants of the photosynthesis equation?
6 CO2 (carbon dioxide) and 6 H2O (water)
Cellular respiration equation
C6H12O6 + 6 O2 —-> 6 CO2 + 6 H2O
Cellular respiration
Process by which cells obtain energy from glucose by breaking down simple food molecules (such as sugar), and releasing the stored energy
Cellular respiration equation
C6H12O6 + 6 O2 —-> 6 CO2 + 6 H2O + ATP (energy)
Stage 1 (cellular respiration)
In the cytoplasm, glucose is broken down into smaller molecules; oxygen is not involved (anaerobic) and only a small amount of energy is released
Stage 2 (cellular respiration)
Takes place in the mitochondria where molecules are broken down even further by chemical reactions - requires oxygen (aerobic) and a great deal of energy is also released (carbon dioxide and and water are also released)
Fermentation
Provides energy for cells without using oxygen
List 2 types of fermentation
- alcoholic fermentation (used in baking)
- lactic acid fermentation (felt in muscles after extreme exertion)
Is photosynthesis used by an autotroph or heterotroph?
Autotroph
Is cellular respiration used by and autotroph or heterotroph?
Both
What is an advantage of using photosynthesis?
Doesn’t rely on other organisms for food
What is a disadvantage of photosynthesis?
No sun = no food
What is an advantage of cellular respiration?
Option to obtain energy without oxygen
What is a disadvantage of cellular respiration?
The organism has to eat regularly
The cell cycle
Regular sequence of growth and division that cells undergo which is divided into 3 main stages
What are the 3 stages of the cell cycle?
Interphase, Mitosis, and Cytokinesis
What is the biggest stage of the cell cycle?
Interphase
What are the functions of cell division?
- growth
- repair damaged structures
- reproduction
Interphase
This is the period before cell division in which the cell grows, makes an identical copy of it’s DNA, and prepares for mitosis
Mitosis
Stage in which the cell’s nucleus divides into 2 new nuclei and one copy of the DNA is distributed into each of the 2 daughter cells
What are the 4 stages of mitosis?
Prophase, Metaphase, Anaphase, and Telophase
What occurs during prophase?
- nuclear envelope dissolves
- chromatin become chromosomes (made of 2 sister chromatids)
- mitotic spindles form
What occurs during metaphase?
- chromosomes are pulled to the middle of the cell (align in the middle)
What attaches the two sister chromatids?
Centromere
What occurs in anaphase?
- sister chromatids are pulled to opposite poles
- spindles begin to shorten
- cell stretches
What occurs in telophase?
- when the sister chromatids reach the poles they detach from the spindle fibers
- sister chromatids then become chromatin
- nuclear envelope reforms
- cell starts to split
Cytokinesis
This process is different depending on the type of cell-
Plant cell: cell plate forms down the middle splitting the cell in half (this process occurs because the cell wall, which is rigid, cannot pinch)
Animal cell: the cell membrane pinches around the cytoplasm, forming a cleavage furrow, splitting the cell in half (this process starts in telophase)
What is the longest phase of mitosis?
Prophase
What does DNA stand for?
Deoxyribonucleic acid
What is the structure of DNA?
Double helix (looks like a twisted ladder)
Who discovered the structure of DNA?
Rosalind Franklin discovered it, but it was first published by by James Watson and Francis Crick
In what year was the structure of DNA published?
1953
What is the role of DNA in your body?
To direct functions
What does DNA contain?
The genetic information for a cell to make proteins and is carried from one generation to the next
What do proteins determine?
A variety of traits, from hair color to an organism’s ability to digest food
What are the building blocks of DNA?
Units called nucleotides
What is a nucleotide made of?
- 5-carbon sugar called deoxyribose
- a phosphate group (which make up the sides of the ladder)
- a nitrogen base (which makes up the rungs of the ladder)
What are the sides of the double helix made up of?
Made up of sugar molecules called deoxyribose, alternating with phosphate molecules
What are the four nitrogen bases?
- adenine
- guanine
- thymine
- cytosine
Nitrogen bases can only pair with certain nitrogen bases, so which pairs with which?
- cytosine only pairs with guanine
- thymine only pairs with adenine
Gene
A Gene is a section of DNA that contains the information to code for one specific protein (made up of a series of bases in a row)
How many chromosomes can a single gene contain?
Anywhere from several hundred to a million or more bases
DNA replication
Is the process in which an identical copy of DNA strand is formed for a new cell
Why is DNA replication important?
Very important since daughter cells need a complete set of DNA to survive
First step of DNA replication
Two sides of DNA molecule unwind and separate (like a zipper unzipping) between the nitrogen bases
Second step of DNA replication
Nitrogen bases in the nucleus pair up with the bases on each half of the DNA
What is a control system?
A control system, made of certain proteins within a cell, directs the timing and sequence of events in the cell cycle
- if something goes wrong in this system, the cell loses control of the cell cycle
Cancer
A disease caused by a disruption to the cell cycle leading to uncontrolled cell division
What do cancerous cells form?
Masses of tissues called tumors
How many types of tumors are there?
2
Benign tumor
Abnormal mass of essentially normal cells that always remain at the original site of growth (can usually be removed with surgery)
Malignant tumor
Mass of cancerous cells that displace normal tissue as it grows. If not killed or removed, this tumor can spread into surrounding tissue, or worse: break off and travel to other parts
What is the spreading of cancer called?
Metastasis
What are environmental causes of cancer?
Smoking, or oil and water pollution
What other things can cause cancer?
- ultraviolet radiation
- genetic factors such as viral infections that damage genes
