unit 44 bio

where is dna located?

nucleus

what does nucleus control?

controls all cell activities and cell division

chromatin

long, thread-like DNA in a non-dividing cell

chromatid

double, coiled, short dna in a dividing cell

centromere

2 identical "sister" chromatids attached at an area in the middle

what happens when cells divide?

sister chromatids separate and 1 goes to each new cell

what are some details about chromosomes?

pass on genetic information, made of dna, every organism has a specific number of chromosomes, replicate before cell division, are visible during cell division.

what are some details about somatic cells

all somatic cells in an organism have the same kind and number of chromosomes. mitosis occurs in these cells.

what does chromosome number have?

every organism has its own specific number of chromosomes

what are the 2 main reasons for why cells divide?

dna overload and exchanging materials

dna overload

if the cell grows to big, there will be an information crisis because as cells increase in size, they do not usually make extra copies of dna

exchanging materials

if the cell grows to big, it would take too long for nutrients and wastes to travel across the cell membrane and through the cell. (surface area to volume ratio)

what does the rate at which materials enter and leave the cell depend on?

surface area of the cell membrane - the total area of the cell membrane

what does the rate at which food and oxygen are used up and waste products are produced depends on?

the cell's volume

since the volume increases much more rapidly than surface area, what happens?

the efficiency of the cell decreases as more volume is gained causing the cell to divide

cell division

the process by which a cell divides into two new daughter cells

how does cell division help dna overload and exchanging materials?

dna overload has each daughter cell to receive a copy of dna. exchanging materials has each new cell increase in surface area to keep the efficiency high.

cell cycle

series of events cells go through as they grow and divide

The cell cycle can be divided into two stages. What are they?

interphase and cell division

interphase

the period between cell divisions; consists of 3 parts.

G1

cell increase in size and makes new proteins and replicates organelles

S

chromosomes are replicated

G2

preparation for mitosis & continued growth

cell division consists of 2 stages. what are they?

mitosis and cytokinesis

mitosis

division of the nucleus into 2 nuclei, each with the same number of chromosomes

cytokinesis

division of the cytoplasm

why do cells need to divide?

* living things grow by producing more cells, not because each cell increases in size
* repair of damaged tissue
* if a cell gets too big, it cannot get enough nutrients into the cell and wastes out of the cell

what is the original cell called?

parent cell

what makes the daughter cell and parent cell similar?

same kind and number of chromosomes

what are the 4 stages of nuclear division?

prophase, metaphase, anaphase, telophase (PMAT)

prophase

sister chromatids coil up. nuclear envelope disappears. spindle fibers form.

metaphase (middle)

spindle fibers connect to chromosomes at the centromere. sister chromatids line up in the middle of cell.

anaphase (apart)

centrioles acts as "anchors" for the spindle fiber to pull against. sister chromatids are pulled apart and become chromatids. spindle fibers pull chromosomes to opposite poles.

telophase (two)

chromatids uncoil. nuclear envelopes form. 2 new nuclei are formed. spindle fibers and centrioles disappear.

cytokinesis

the division of the rest of the cell (cytoplasm) after the nucleus divides

how are cytokinesis in animal cells?

the cytoplasm pinches in

how are cytokinesis in plant cells?

a cell plate forms

autotrophs

organisms that are able to use light energy from the sun to produce their own food

heterotrophs

organisms that must obtain energy from the foods that they consume

what is the main energy "currency" of the cell called?

ATP

what is the abbreviation for ATP?

adenosine triphosphate

what are the parts in a ATP molecule?

adenine (contains nitrogen), a 5-carbon sugar (ribose), three phosphate groups

where is alpha phosphate located?

closest to the ribose

where is beta phosphate located?

middle of the phosphate

where is gamma phosphate located?

furthest from the ribose

why are gamma phosphate removed?

to release energy

phosphorylation

the addition of a phosphate group to ADP OR the removal of a phosphate group from ATP

most cells have what?

ADP, adenosine DIphosphate (half charged battery)

When a cell has energy available, how can it store small amounts of that energy?

by adding a phosphate group to ADP, producing ATP

atp is like what?

a fully charged battery

the energy stored in ATP is released when ATP does what?

converts into ADP

adding a phosphate group does what?

stores energy

subtracting a phosphate group does what?

releases energy

what are cellular uses of ATP?

active transport in cell membranes and movement of organelles within the cell

ATP is not good at what?

storing large amounts of energy over long periods of time.

Cells keep only a small amount of _________ on hand

ATP

how can cells generate ATP from ADP?

by using the energy in carbohydrates like glucose

photosynthesis uses the energy of sunlight to convert what into what?

to convert water and carbon dioxide into oxygen and high-energy sugars like glucose

What is the equation for photosynthesis?

6CO2 + 6H2O + light energy = C6H12O6 + 6O2.

pigments

plants gather the sun's energy with light-absorbing molecules

chlorphyll

the plants' principle pigment. found inside a plant's chloroplast

why are plants green?

chlorophyll reflects green light

photosynthesis needs what in order to make glucose?

water, carbon dioxide, light and chlorophyll

chloroplast

where the reactions of photosynthesis take place

thylakoids

the photosynthetic membranes

grana

thylakoids arranged into stacks

stroma

the fluid-filled space around the grana. like cytoplasm.

the reactions of photosynthesis are broken down into 2 main parts. what are they?

light dependent reactions and light independent reactions or calvin cycle

light dependent reaction

requires light in order to occur, happens in the thylakoid membrane, the light reactions produce oxygen gas and convert ADP and NADP+ into the energy carriers ATP and NADPH

what is used in light reaction?

Water (H2O)

what is produced when the water is split?

oxygen gas (O2)

what is the purpose of the light dependent reaction?

to produce ATP and NADPH that allow the dark reaction (Calvin Cycle) to happen

for review, light dependent reactions make what?

atp and nadph

where in the light dependent reaction does it start?

photosystem 2

as the electrons move along the ETC, proteins pump what?

H+ into the thylakoid from the stroma

how does NADP+ turn into NADPH?

electrons from the ETC and H+ in the stroma and combine with NADP+ converting NADP+ into NADPH

where did the H+ ions come from?

some from splitting water and some were pumped in through proteins pumps.

the buildup of H+ makes...

the thylakoid strongly positive compared to the stroma

how does ADP convert to ATP?

the difference in charge in the thylakoid and stroma, provides a gradient that converts the adp.

where must H+ pass through?

ATP synthase, thus making ATP

the dark reaction (Calvin cycle)

uses the ATP and NADPH produced in the light reaction to produce high-energy sugars like glucose

what does calvin cycle not require?

light

where does the calvin cycle occur?

the stroma of the chloroplast

the plant uses the sugars for energy to build what?

build more complex carbohydrates like starches and cellulose

what does the plant need for dark reactions to occur?

carbon dioxide, ATP, and NADPH

what factors affect photosynthesis?

water, temperature, intensity of light

how does water affect photosynthesis?

A shortage of water can slow or stop photosynthesis.

how does temperature affect photosynthesis?

the enzymes required for the reactions of photosynthesis function best between 0 degrees and 35 degrees celcius

how does the intensity of light affect photosynthesis?

increasing light intensity increases the rate of photosynthesis

cellular respiration is the reverse of?

photosynthesis

glucose

serves as the source of energy for cellular processes for all organisms

cellular respiration

the process that releases energy by breaking down food molecules in the presence of oxygen.

what is the equation for cellular respiration?

6O2 + C6H12O6 -> 6CO2 + 6H2O + Energy

matrix

the fluid filled cinter

Cristae

where the inner membrane folds

what is the purpose for cristae?

to increase the surface area for the ETC

glycolysis

the process in which one molecule of glucose is broken in half, producing two molecules of pyruvic acid.

which organisms do glycolysis?

all organisms

where does glycolysis occur?

in the cytoplasm

is glycolysis anaerobic or aerobic?

anaerobic