biology exam terms

Cell division

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

why do cells divide

* become too big and overload
* body isn’t able to get waste products and nutrients in and out

how would you describe the way in which a multicellular organism increases in size

as the cell collects more nutrients, it needs more space to hold those nutrients, so it grows and increases in size. The cell then divides if there isnt enough dna for the whole cell now that the dna is large

why do cells stay small

so that cells cells are able to do their job and connect function into the body.

why is surface area important for a cell

then we know how big a cell can become. and know whether or not is is going to divide. and how much cell membrane there is to make nutrients

purposes of cell cycle (there are three)

* reproduce
* repair
* recycle

why is it important for new cells to be produced in the original cell

so they could have the same function as before in the correct place (tissues cells muscle cells, ect.)

what are the two phases of the cell cycle

interphase and mitotic phase

what are the stages if cell division

* interphase
* prophase
* metaphase
* anaphase
* telophase
* cytokinesis

what happens in interphase?

the cell grows and replicates DNA

what happens in prophase

the chromatin condenses into chromosomes. the centrioles separate and a spindle begins to form. the nuclear envelope breaks down

What happens in Metaphase?

the chromosomes line up across the center of the cell. each chromosome is connected to a spindle fiber at its centrosome

what happens in anaphase

the sister chromatids separate into individual chromosomes and are moved apart

what happens in telophase

the chromosomes gather at opposite ends of the cell and lose their distinct shapes. the nuclear envelope will form

what happens in cytokinesis

the cytoplasm pinches itself in half. each daughter cell has an individual set of duplicate chromosomes.

cyclin

protein that regulates the timing of the cell cycle in eukaryotic cells.

what are the reactants and products of matter in photosynthesis

carbon dioxide and water → chemical energy

what is photosynthesis

a process that allows plants to transform light energy into chemical energy

where does photosynthesis happen?

chloroplast

why does the equation for photosynthesis have to be balanced

atoms cannot be destroyed or produced.

autotroph

organisms that make their own food

heterotroph

organisms that cannot use the sun’s energy directly. they get energy from the foods that they consume.

ATP

one of the principal chemical compounds that cells use to store and release energy

biosynthesis

the process in your body that turns simple structures into complex structures .

thylakoid

saclike photosynthetic membranes located in the chloroplast

stroma

the region outside the thylakoid membranes. where the calvin cycle takes place.

NADP+

 a coenzyme that functions as a universal electron carrier, accepting electrons and hydrogen atoms to form NADPH, or nicotinamide adenine dinucleotide phosphate. 

calorie

the amount of energy needed to raise the temperature of 1 gram water 1 degree celsius

glycolysis

a pathway that releases a small amount of energy

cellular respiration

the process that releases energy by breaking down glucose and other food molecules in the presence of oxygen

NAD+

a crytical coenzyme found in every cell in your body. it is involved in thousands of metabolic processes

fermentation

an anaerobic process in which energy can be released from glucose even though oxygen is not available.

anaerobic

without oxygen

how many calories make up 1 Calorie

1000

cellular respiration begins with a pathway called

glycolysis

what are the three main stages of cellular respiration

glycolysis, Krebs cycle, and electron transport chain

where does glycolysis take place

in the cytoplasm

What do all cells have to make

ATP

genetics

the scientific study of heredity

fertilization

during sexual reproduction when male and female cells join

true- breeding

if they were allowed to self pollinate they would produce offspring identical to themselves

trait

a specific characteristic

hybrid

the offspring between crosses of parents with different traits

gene

the chemical factors that determine traits

alleles

the different forms of a gene

segregation

separation of alleles

gametes

sex cells

gregor mendel

founder of the study of genetics

probability

the likelihood that a particular event will happen

punnett squares

a diagram showing the gene combinations that might result from

homozygous

organisms that have two or three identical alleles for a particular trait

heterozygous

organisms that have two different alleles for a particular trait

phenotypes

physical characteristics

genotypes

genetic makeup

the passage of dna from one generation to the next is called

inheritance

a segment of dna that codes for a particular trait

gene

homologous

each of four chromosomes that came from the male parent has a corresponding chromosome from the female parent

diploid

contains both sets of homologous; two complete sets of genes and two complete sets of chromosomes

haploid

contains a single set of homologous chromosomes and genes

meiosis

a process of reduction division in which the number of chromosomes per cell is cut in half

interphase 1

cells undergo a round of dna replication, forming duplicate chromosomes

prophase 1

each chromosome pairs with its corresponding homologous chromosome to form a tetrad

metaphase 1

spindle fibers attach to the chromosomes

anaphase 1

the fibers pull the homologous towards the opposite of the ends of the cell

telophase and cytokinesis

nuclear membranes form. the cell separates into two cells

meiosis 2

meiosis 1 results in two haploid daughter cells, each with half the number of chromosomes as the original cell

metaphase 2

the chromosomes line up in a similar way to the metaphase stage of meiosis

anaphase 2

the sister chromatids separate and move toward opposite ends of the cell

telophase 2 and cytokinesis

meiosis 2 returns to the four haploid daughter cells

DNA replication

The process of copying DNA

semi conservative

each original strand of dna is used as a template for adding new nucleotides

enzymes

active proteins

heliacase

responsible for separating the two strands of dna

dna polymerase

responsible for adding on new nucleotides

antiparallel

run parallel but go in opposite directions

name the four biomolecules

carbs, lipids, nucleic acids, protein

where is dna stored in the cell

nucleus

messenger rna

instructions that serve messengers from dna to the rest of the cell.

Ribosomal RNA

ribosomes are made up of several proteins as well as a form of RNA which is ribosomal RNA

transfer rna

transfers each amino acid to the ribosome as it is specified by coded messages in rna

transcription

the process by which a cell makes an RNA copy of a piece of DNA. 

Rna polymerase

an enzyme in molecular biology that synthesises RNA from a DNA template.

codon

a sequence of three nucleotides which together form a unit of genetic code in a DNA or RNA molecule.

translation

In biology, the process by which a cell makes proteins using the genetic information carried in messenger RNA (mRNA).

anticodon

complementary to RNA codon

mutations

changes in genetic material

point mutations

mutations that occur at a single point in the dna sequence

frameshift mutations

a mutation involving the insertion or deletion of a nucleotide

polyploidy

the condition in which an organism has extra sets of chromosomes