Unit 4 Study Guide Flashcards
Food contains ______ main groups of ________ molecules (also called ________).
three, organic, biomolecules
These organic food molecules are made of many ____ joined together.
atoms
What are biomolecules?
Biomolecules provide energy and building blocks for our bodies.
What does “organic molecule” mean?
Molecule that contains carbon atoms bonded to hydrogens.
___ are a type of _____.
Fats, lipid
____ are part of a group of molecules called _____.
Fats, lipids
What do all lipids have in common?
What all lipids have in common is that they do not dissolve in water.
What are fats made of?
They are made of smaller units called fatty acids joined to glycerol.
What is the scientific name for three fatty acids joined to glycerol?
Triglyceride
Fatty acids can be __________ or __________.
saturated, unsaturated.
What are saturated fats?
Typically solid at room temperature. Typically from animal sources. (Ex. Butter)
What are unsaturated fats?
Typically liquid at room temperature. Typically from plant sources and are healthier. (Ex. Oil)
What are trans-unsaturated fats (trans fats)?
Most are made artificially by adding hydrogen to unsaturated fatty acids.
Which fat should you avoid eating?
Trans fats. Used in foods that have to sit on counters for a while.
Fats are ______ to fatty acids.
digested
_______ are delivered to your cells to be used for _____.
Fatty acids, energy
What are fat cells/stored fat?
Excess fatty acids are stored in fat cells. Stored fat is a source of insulation and energy between meals.
_______ is ANOTHER type of ____.
Cholesterol, lipid
What is cholesterol?
Helps your body make cell membranes, many hormones, and vitamin D.
Only ________ contain cholesterol.
animal-based foods.
Your _____ also synthesizes cholesterol.
cells
What’s another word for monosaccharides?
Sugars
What do these monosaccharides (sugars) include?
- Glucose
- Fructose
- Galactose
What are two monosaccharides joined together called?
Disaccharides
What do these disaccharides include?
- Lactose (milk sugar)
- Maltose
- Sucrose (table sugar)
Sugars are a source of _______________.
immediate energy
How are monosaccharides digested?
Monosaccharides are directly absorbed into your bloodstream from the small intestine.
How are disaccharides digested?
Disaccharides are quickly broken down into monosaccharides.
_______________ need to be digested into monosaccharides.
Larger carbohydrates
What are larger carbohydrates?
Large carbohydrates are long chains of monosaccharides.
What do these large carbohydrates include?
- Starch
- Cellulose
- Glycogen
- Chitin
Cellulose is a major component of plant cell walls. Humans are unable to digest cellulose so it goes to the colon undigested. Another name for cellulose is…
dietary fiber
We store excess carbs as _______.
glycogen
How is glycogen stored for plants and animals?
It’s stored as starch in plant cells and as glycogen in animal cells.
Where in the human body is glycogen stored?
Glycogen is stored in the liver, muscles, and it’s the first source of energy in between meals.
_____ are not a major source of energy.
Protein
What are the three main purposes of proteins?
- Provide structure for animal cells.
- Build muscles with exercise.
- Produce enzymes, antibodies, and some hormones.
True or False: Protein is only found in animal products.
False
What are proteins made of?
Amino acids
What are proteins?
Proteins are long chains of amino acids folded into 3-dimensional structures. The shape is important for its function.
How do cells use amino acids?
Cells use amino acids to build the proteins that make up your body.
Besides building proteins, how else can amino acids be used?
Cells can also use amino acids for energy if fats and sugars are not available.
Excess amino acids are stored as ___.
fat
Lactose is a _______ in milk.
sugar
Lactose is ______ in the small intestine.
digested
What is the process of breaking down lactose?
When H2O is added to lactose (reactants) they’re broken down by a lactase enzyme into glucose and galactose.
What are enzymes used for?
Enzymes speed up chemical reactions; they lower the energy threshold for a chemical reaction to happen.
What are the products of a chemical reaction?
They are what you end up with after the chemical reaction.
All enzymes are…
proteins
Are enzymes similar or different from one another?
Enzymes are specific: different enzymes catalyze different chemical reactions.
Most human adults do not have a lactase enzyme. As a result…
lactose goes from the small intestine to the colon undigested.
If lactose is digested in the small intestine of someone who is lactase persistent, blood glucose will quickly…
increase
Diabetes mellitus is a _________ condition.
chronic health
What is diabetes?
The body cells of individuals with diabetes don’t take up enough glucose from the bloodstream.
Diabetes is a problem with _____________.
blood glucose regulation
In individuals with diabetes mellitus, blood glucose levels _________________ after a meal.
remain high for a longer period
What happens if blood sugar remains too high?
Over time, high blood glucose can damage organs.
With diabetes, body cells are also not _____________.
getting enough glucose
What is glucose homeostasis?
Signals from hormones in the body maintain constant glucose levels in the blood.
What is insulin?
The hormone insulin signals to body cells to take up glucose.
What is the purpose of hormones?
Most hormones bind to receptors on cells. The binding provides a signal for the cell to respond in some way.
With diabetes, the body either…
doesn’t make enough insulin or doesn’t respond to insulin.
What is type 1 diabetes?
Primary caused by genetics; body does not produce insulin. Can be treated with insulin injections.
What is type 2 diabetes?
Caused by many genes and the environment; cells of the body do not respond to insulin. Can be treated with diet, exercise, and medications.
Your body needs __________ so that nutrients can go from the small intestine to the bloodstream.
enzymes to digest food
Your body cells need to _________ from the bloodstream.
take up nutrients
________ regulates the amount of glucose and other nutrients in the bloodstream.
Hormones
Nucleic acids are ____ and ___.
DNA, RNA
What are nucleic acids?
They contain the genetic blueprint of a cell and have instructions for the functioning of the cell.
What is DNA?
DNA codes for proteins that make up your cells.
DNA is made of _________.
nucleotides
What are the four nucleotides in DNA?
- Cytosine (C)
- Guanine (G)
- Adenin( A)
- Thymine (T)
Nucleotides are joined together into a _______.
double-helix
DNA is a chain of the ___________.
four nucleotides
One molecule of DNA is made of…
two chains (strands) of paired nucleotides.
DNA in your cells is packaged in _______.
chromosomes
What are chromosomes?
Chromosomes are large molecules of DNA.
What are genes and traits?
Genes are sections of DNA that affect your traits.
Most genes code for…
proteins
How many genes do humans have?
20,000
What is the sequence of nucleotides made for?
The sequence of nucleotides in your genes is a code for making proteins.
What is the purpose of the order in nucleotides?
The order of nucleotides in a gene “spells out” the amino acids that will make the protein encoded by that gene.
What are variations in genes?
If some of the nucleotides in a gene change, that gene could produce a slightly different protein.
______ in genes can affect traits.
Variations
What are traits?
Traits are the physical and behavioral characteristics that we have.
Why are some traits affected by DNA?
Because DNA encodes proteins which then affect traits. However, the environment can also influence your traits.
Why did scientists study twins when it pertains to genes versus traits?
Twin studies were used to determine the heritability of traits.
What are identical twins?
Identical (monozygotic) twins develop from the same fertilized egg so they have identical DNA.
What are fraternal twins?
Fraternal (dizygotic) twins develop from two different eggs fertilized by two different sperm, so their DNA is not identical.
A variation in a _______ can have a large effect on height.
single gene
What is Laron syndrome?
Laron syndrome is a condtion in which individuals are typically under 4.5 feet tall.
What causes Laron syndrome?
It’s caused by a mutation in a gene that codes for the growth hormone receptor.
Height is determined by ______ each with a ______.
many genes, small effect
Scientists have identified over ______ DNA variations associated with height.
3,290
Some traits (like ______) are completely __________.
blood type, genetically determined
Most traits have both _______ and _______ components (like ______).
genetic, environmental, height
Some traits are completely determined by the _________- not ________.
environment, inherited
Bacteria reproduce by _______ reproduction
asexual
What is mitosis?
From one cell produce two almost identical cells.
Can bacteria have DNA mutations?
Mutations can happen during DNA replications and because bacteria reproduce very fast the population can change over time.
Humans reproduce by __________.
sexual reproduction
What is fertilization?
Fertilization is the fusion of sperm and egg from two different parents to form a zygote (single cell).
What are diploids?
Organisms that have two full sets of chromosomes are called diploids.
What are haploids?
Haploids are organisms that have one set of chromosomes.
Humans have __ pairs of ________ and __ pair of ______ (XX or XY) for a total of __ chromosomes.
Humans have 22 pairs of autosomes and 1 pair of allosomes (XX or XY) for a total of 46 chromosomes.
What are continuous traits?
Traits that vary among a continuum or spectrum. (Ex. Height)
What are discrete traits?
Traits you can put in discrete categories. (Ex. The color of sunflower pedals.)
What is a type of discrete trait?
Binary traits they come in two versions.
What are two possible ways traits are inherited?
Monogenic or polygenic inheritance.
What is monogenic inheritance?
One gene is primarily responsible for one trait; a difference in this gene has a large effect; typically rare.
What is polygenic inheritance?
Many genes affect a trait; usually differences in each of these genes has a small effect and it’s the combination of all these genes that determines the trait; most human traits.
Pairs of autosomes are called _______________.
homologous chromosomes
What are homologous chromosomes?
Homologous chromosomes are the same length and have the same genes in the same locations.
True or false: homologous chromosomes are not identical. They can have some DNA variations.
True
What is the composition of chromosomes in gametes?
Gametes only have one full set of chromosomes.
What are zygotes?
During fertilization, the gametes combine so that is how you end up with a diploid zygote with one set of chromosomes from each parent.
What is meiosis?
A kind of cell division called meiosis produces haploid gametes.
What is the purpose of meiosis?
The purpose of meiosis is to go from a cell with two sets of chromosomes (2n) to gametes with one set of chromosomes (n).
Meiosis starts with a _________.
diploid cell
What is the first step in meiosis?
Homologous chromosomes are duplicated.
What is the second step in meiosis?
After homologous chromosomes are duplicated, the chromosome pairs line up in the middle of the cell, they swap pieces.
What is crossing-over in terms of the second step of meiosis?
When chromosomes are next to each other, they swap pieces. This is called crossing over.
What is step three in meiosis?
The first division (Meiosis 1) is when homologous pairs separate into two different cells.
What is independent assortment in terms of the third step of meiosis?
The cells that are produced randomly receive different homologous chromosomes. This is called independent assortment.
What is the fourth step of meiosis?
Second division (meiosis 2) is when duplicated chromosomes separate into 4 cells.
What are these separate four cells called in meiosis 2?
These are called gametes
What are the three processes during meiosis that make gametes unique?
- Mutation during DNA replication
- Crossing over
- Independent assortment
During meiosis, what causes variations in DNA sequences?
- These are caused by errors in how DNA replicates.
- Can be caused by errors in chromosome separation during meiosis.
- Can be caused by variations in chromosome types which are caused by errors in crossing over.
What are macromolecules?
They are large organic molecules that are built from smaller organic molecules.
What are the four major groups of macromolecules?
- Carbohydrates
- Lipids
- Proteins
- Nucleic acids
Where are carbohydrates found?
- Grains
- Fruits
- Vegetables
What are three types of carbohydrates?
- Monosaccharides
- Disaccharides
- Polysaccharides
Lipids are a diverse group of compounds united by a common feature: they are ___________ or insoluble in water.
hydrophobic
What are nucleotides?
A DNA molecules comprises two chains (also called strands) or nucleotides.
What is the main cause of a different number of chromosomes in some individuals?
Nondisjunction during meiosis
Alleles of _____________ are inherited _________ of one another.
different genes, independently
